View source for Circuit Board Manufacturers Near Me China Pcb Assembly Services China

If you follow this tutorial step by step,<br><br>then even if you have never ever designed any boards before,<br><br>by the end of this tutorial, you will have this board.<br><br>You will know, how to design it.<br><br>You will know, how to upload some firmware on this board<br><br>and how to bring it to life.<br><br>In this tutorial, we are going to use<br><br>this EasyEDA software<br><br>and JLCPCB services.<br><br>I need to say, this video is not sponsored.<br><br>Only the reason why<br><br>we are going to use this software and<br><br>why we are going to use these services<br><br>is because they are simple to use, and they are<br><br>not expensive.<br><br>Actually, this EasyEDA software is completely free.<br><br>You just need to register,<br><br>and<br><br>you don’t even need to install anything.<br><br>This EasyEDA software runs directly in your browser,<br><br>and this is the software which we will use to design our schematic<br><br>and also PCB.<br><br>Okay?<br><br>So, in this tutorial,<br><br>you will learn how to design this schematic.<br><br>I will also explain<br><br>everything what we are going to do<br><br>and why we are going to choose specific components.<br><br>I will explain what<br><br>you need to be careful about<br><br>when you will be designing your own boards<br><br>and also, I will also explain,<br><br>how to connect everything together.<br><br>So, this can help you to understand,<br><br>what you may want to think about<br><br>when you will be connecting components on your own board.<br><br>Then, once we have the schematic, we will also learn,<br><br>how to design PCB.<br><br>Again, I will explain,<br><br>what you may want to think about, when<br><br>you will be doing layout, when you will be drawing the tracks,<br><br>when you will be placing components<br><br>and once,<br><br>we designthe schematic and board,<br><br>this is how it is going to look.<br><br>Then, we will<br><br>learn how to generate all the files<br><br>which are needed to manufacture your PCB.<br><br>We will learn how to generate all the files<br><br>which are needed to assemble your board,<br><br>we will send<br><br>these files into production.<br><br>If you like you can do it too.<br><br>And then, once you receive<br><br>your boards, this is how it is going to look.<br><br>Once you have your boards,<br><br>we will learn how to write simple software,<br><br>how to upload it on your board<br><br>and how to bring your board to life.<br><br>I really hope you will find this tutorial useful and<br><br>here it is.<br><br>To design the schematic and PCB,<br><br>we are going to use website which is called<br><br>EasyEDA.<br><br>Just google for this<br><br>or search for this.<br><br>Click here,<br><br>register on this website and then, click on this EasyEDA Designer.<br><br>The registration is free, so you don’t have to pay anything<br><br>and also, you don’t need to install anything, because<br><br>we are going to design the schematic and PCB directly<br><br>in web browser.<br><br>Move cursor over File,<br><br>New,<br><br>left click on Project,<br><br>name your project for example My Board<br><br>and Save.<br><br>Left click on My Board project, be sure it is selected<br><br>and then File,<br><br>Save<br><br>and now we<br><br>save this schematic page inside of our project.<br><br>We are going to rename this schematic page.<br><br>Right click,<br><br>Modify, let’s call it My<br><br>Schematic<br><br>and we are going to add [https://szeastwin.evlla.com/ Eastwin PCB], so right click on the Project,<br><br>New PCB,<br><br>Apply,<br><br>click on File,<br><br>Save.<br><br>Right click,<br><br>Modify and we are going to call it My PCB.<br><br>Next,<br><br>we are going to have a look at specification of our board<br><br>and it’s going to be very simple.<br><br>On the board we would like to have a microcontroller,<br><br>RGB LED, accelerometer,<br><br>push button,<br><br>we would like this board to be battery powered<br><br>and it has to be really small.<br><br>So, let’s start with something what is quite easy to add<br><br>into our schematic.<br><br>First, we are going to add this RGB LED.<br><br>Go on JLCPCB website,<br><br>just search for JLCPCB,<br><br>left click,<br><br>then Resources,<br><br>SMT Parts Library.<br><br>Here we can see the list of all the components which they<br><br>can use for the assembly,<br><br>and we would like to find LED, so go here,<br><br>Light Emitting Diodes.<br><br>In this<br><br>filter, we would like to only work with components which are in stock,<br><br>and we would like to find RGB LED.<br><br>Apply.<br><br>There are only three options what we can use,<br><br>so let’s have a look on the first one, left click here,<br><br>left click on download to see the datasheet<br><br>and<br><br>this is not the kind of LED which we would like to use, because<br><br>in this LED we cannot directly control the<br><br>RGB LEDs. You can see,<br><br>this is special diode, which can be connected in series.<br><br>So, let’s go back,<br><br>I’m going to close this.<br><br>Open the next component, left click,<br><br>open datasheet of this component, left click<br><br>and this is exactly what we need.<br><br>Here you can see this is the component, this is the LED<br><br>and inside there are three LEDs.<br><br>They have common anode<br><br>and then we can individually switch on or switch off<br><br>these RGB LEDs inside of this component.<br><br>Let’s go back.<br><br>We are going to copy the manufacturer part number,<br><br>just hover cursor here, left click Copy,<br><br>go back into our schematic,<br><br>double click on the schematic page,<br><br>go on Library, left click.<br><br>Here Ctrl+V<br><br>and search for our LED,<br><br>left click to select,<br><br>left click on Place,<br><br>to rotate press spacebar<br><br>and left click to place the LED inside of our schematic,<br><br>press Escape.<br><br>Let’s have a closer look at this LED.<br><br>You know,<br><br>let’s talk about the things what you may<br><br>need to think about when you are choosing components<br><br>for your project.<br><br>So, first I’m going to click on this Library<br><br>and here you can see the<br><br>LED which we choose for our project<br><br>and what is important is this icon,<br><br>SMT icon, which says "Assembled",<br><br>because this means, that when we will be ordering the<br><br>PCBs and when we will ask this company to assemble,<br><br>to fit the components,<br><br>then this LED is available for this service,<br><br>so they can fit it.<br><br>You can see it also down here,<br><br>there, they have these LEDs in stock,<br><br>380 is available for JLCPCB SMT Service,<br><br>so this is important.<br><br>Maybe you don’t want to use components which are not in stock,<br><br>and<br><br>we would like to be able to buy this<br><br>LEDs in minimum quantity 1.<br><br>This is also perfect,<br><br>so we don’t need to pay for, I don’t know, 1000 pieces of these LEDs.<br><br>When we go and when we have a look inside of the datasheet,<br><br>there are few parameters which are important,<br><br>when you are selecting LED for your project.<br><br>You may want to have a look on this forward current<br><br>which is 5 milliamps<br><br>and maximum is 10 milliamps.<br><br>This is important because<br><br>some LEDs, they need high current,<br><br>I don’t’ know, 20 milliamps to light up<br><br>>and for battery powered device<br><br>>maybe we would like to use LEDs with low current<br><br>>needed to light up the LED<br><br>>So, 5 milliamps is perfect<br><br>>and also what is important is this forward voltage<br><br>>For red LED it is 2.1 volt<br><br>>for green 3.1 and for blue it’s 3 volts<br><br>>This is the voltage, which is across the diode<br><br>>and it basically means<br><br>>for example that you cannot powe<br><br>>these LEDs with 1.5 volt<br><br>>because then they would not work<br><br>>Okay? They need this forward voltage to work<br><br>>It means we may need to power up these LEDs maybe wit<br><br>>5 volts for example<br><br>>In this case<br><br>>in this RGB LED is als<br><br>>quite important maybe to use this common anode<br><br>>because when we have a look at the finished schematic<br><br>>I’m going to open this finished schematic<br><br>>here you can see, that we would like to contro<br><br>>this ground connection to this each individual LED<br><br>>So, this is how you normally control LED<br><br>>by connecting ground to LED, okay<br><br>>If they would not have common anode<br><br>>then it could be little bit more tricky<br><br>>You would have to use different circuit<br><br>>So, this is also perfect<br><br>>common anode is exactly what we would like to use<br><br>>It means<br><br>>thi<br><br>>LED is exactly what we would like to have in ou<br><br>>schematic, and we can plac<br><br>>another component<br><br>>I’m going to open our specification agai<br><br>>and the next what we would like to place into our schematic is accelerometer<br><br>>Let’s go back t<br><br>>SMT Parts Library<br><br>>click on All Categorie<br><br>>and in Sensors<br><br>>Motion Sensors – Accelerometer<br><br>r>check this In Stock only componen<br><br>r>and there are not so man<br><br>r>We would like to use maybe the cheapest on<br><br>r>so I’m going to have a look what is t<br><br>r>price for 1 piec<br><br>r>It is $2.1 for this on<br><br>r>$4.<br><br>r>$7<br><br>r>$1<br><br>r>$1.<br><br>r>$<br><br>r>$2.<br><br>r>$1.<br><br>r>So, this is the cheapest o<br><br>r>and we would like to double check the datashee<br><br>r>I’m going to close this datasheets which are her<br><br>r>This one and this one, we don’t need them anymo<br><br>r>and I’m going to op<br><br>r>datasheet for this accelerometer, left clic<br><br>r>Our board is going to be very smal<br><br>r>so first we need to double check the size of th<br><br>r>acceleromet<br><br>r>and it is only 2 x 2 millimeter<br><br>r>It’s like 80 x 80 mils, it’s very smal<br><br>r>And becau<br><br>r>our board is battery powered, we would like to be su<br><br>r>this chip i<br><br>r>or this chip has low current consumptio<br><br>r>0.9 microamp in standb<br><br>r>This is really goo<br><br>r>We are going to power up this chip by 3.3 vol<br><br>r>and this is up to 3.6, so this is perfec<br><br>r>We would like to use I2C for communicatio<br><br>r>because it’s like super simple interface for communicatio<br><br>r>And als<br><br>r>we would like to be sur<br><br>r>there is an interrupt pin which can wake up our syste<br><br>r>I need to search for this informatio<br><br>r>So, I’m going to scroll down little bi<br><br>r>This is the senso<br><br>r>some power<br><br>r>some other pin<br><br>r>The best will be just find table with pin descriptio<br><br>r>It is here, you can se<br><br>r>Okay, so this is address pi<br><br>r>This is just to connect it to ground or powe<br><br>r>I2C Serial Dat<br><br>r>Powe<br><br>r>This is just, this just need to be connected to groun<br><br>r>This is the interrupt pin, this is perfect, this is exactly what we nee<br><br>r>Ground, power, ground a<br><br>r>serial clock. Oka<br><br>r>This is super simple chip. It has everything what we nee<br><br>r>only what I would like to check is how this physical interru<br>r>work<br><br>r>So, let’s search for motion detection or something like tha<br><br>r>Motio<br><br>r>motion interrup<br><br>r>This chip h<br><br>r>"threshold interrupt triggered by internal digital wake-up engin<br><br>r>and "the wake-up event can be programmed to be reported on physical pin<br><br>r>This is exactly what we need, oka<br><br>r>So, this chip c<br><br>r>basically dete<br><br>r>movement and then it wi<br><br>r>change the status of th<br><br>r>INT p<br><br>r>and we can use it to wake up our [https://openclipart.org/search/?query=microcontroller microcontroller<br><br>r>Oka<br><br>r>We can use this chip in our schematic, everything what we have to <br><br>r>is go back to this SMT Parts Librar<br><br>r>copy manufacturer part numbe<br><br>r>go back into our schemati<br><br>r>Librar<br><br>r>Ctrl+<br><br>r>search for this acceleromete<br><br>r>Be sure there is this S<br><br>r>icon, left clic<br><br>r>Be sure it is in stock, we can buy it <br><br>r>1, in minimum quantity 1 piec<br><br>r>click on Plac<br><br>r>put it inside of our schematic, left cli<br><br>r>and press Escap<br><br>r>When we go back into our specificatio<br><br>r>next, what we would like to place into our schematic is push butt<br><br>r>and there is nothing really special about push butto<br><br>r>When y<br><br>r>go into SMT Parts Librar<br><br>r>you can go to All Categori<br><br>r>a<br><br>r>here Pushbuttons, Tactile Switche<br><br>r>you can find any button which you lik<br><br>r>but I use this on<br><br>r>so if you like, you can use same, search for this numbe<br><br>r>A<br><br>r>I use it because it is this kind of standard butto<br><br>r>Copy this manufacturer part numbe<br><br>r>go into our schemati<br><br>r>click on Librar<br><br>r>Ctrl+<br><br>r>search for this butto<br><br>r>left clic<br><br>r>It is available for JLCPCB SMT servi<br><br>r>and minimum quantity 1<br><br>r>I need to be honest, I don’t exactly kno<br><br>r>if it means that when we use their service, <br><br>r>have to buy at least minimum 10 of these switche<br><br>r>but I checked the other switches a<br><br>r>many of them, they have minimum quantity 10, so<br><br>r>really didn’t spend much time investigati<br><br>r>what exactly this means. It’s oka<br><br>r>Click on Plac<br><br>r>left click to place this button into our schemat<br><br>r>and press Escap<br><br>r>When we go back into our specificatio<br><br>r>only what left to place into our schematic is the microcontrolle<br><br>r>So, open t<br><br>r>SMT Parts Librar<br><br>r>go to All Categorie<br><br>r>Embedded Processors & Controlle<br><br>r>and from all these manufacturer<br><br>r>we would like to use something simpl<br><br>r>so maybe we would like to use something from ST Microelectroni<br><br>r>or something from MICROCHI<br><br>r>I’m going to click on MICROCHI<br><br>r>Again, we would like to use only the components which are in sto<br><br>r>and from this lis<br><br>r>many of these cores are little bit more comple<br><br>r>we don’t really need the<br><br>r>The simplest thing will be probably this 8-bit PIC microcontrolle<br><br>r>but this is not the right one, because you can se<br><br>r>there are not many and this one <br><br>r>too big, 80 pins, we don’t need 80 pins, we don’t need 44 pi<br><br>r>and this is too small, 8 pins i<br><br>r>it’s not enough for what we nee<br><br>r>I’m going to reset th<br><br>r>and I’m going to select this on<br><br>r>Okay? This looks bette<br><br>r>Appl<br><br>r>There are still number of microcontroller<br><br>r>what we can choose fro<br><br>r>So, it means we can have a look on some low power suppo<br><br>r>in our microcontrolle<br><br>r>because we are going to use battery powered devic<br><br>r>so ideally maybe it could work with some low voltage<br><br>r>1.8 to 3.<br><br>r>Appl<br><br>r>And only one lef<br><br>r>So, let’s have a look at this microcontrolle<br><br>r>I’m going to open datasheet, left clic<br><br>r>Scroll do<br><br>r>and we are going to check if there is everything what we nee<br><br>r>But first, we would like to check the siz<br><br>r>because we would like to design something really smal<br><br>r>The maximum width of P<br><br>r>should be like 1 centimeter, 400 mils or les<br><br>r>And the size of this microcontroller is 5.3 x 7.2 millimete<br><br>r>It is li<br><br>r>200 x 280 mils or something like thi<br><br>r>So, it’s going to fi<br><br>r>this is goo<br><br>r>A<br><br>r>we would like to check if there is internal oscillato<br><br>r>because we don’t want to add a<br><br>r>like extra components and there is internal oscillato<br><br>r>this is goo<br><br>r>1.8 to 3.6 volt operation for this PIC16LF par<br><br>r>PIC16LF that’s the part what we are going to us<br><br>r>Sleep mode 20 nanoam<br><br>r>for PIC16LF par<br><br>r>This is also, this is really really good, because for batte<br><br>r>powered device this is very importan<br><br>r>Up to 17 I/O pin<br><br>r>programmable weak pull-up resistors, this is also good, because th<br><br>r>we can sa<br><br>r>space on some of the component<br><br>r>We don’t need to add ext<br><br>r>external pull-up<br><br>r>Programmable interrupt-on-change pins, this is importa<br><br>r>because we would like <br><br>r>support interrupt for the push butt<br><br>r>and also interrupt coming from the acceleromete<br><br>r>And we would like to have at least 3 PWM outpu<br><br>r>for the LEDs to regulate the intensit<br><br>r>There are<br><br>r>in CCP module<br><br>r>and it looks like there are also some ECCP modules with PWM suppor<br><br>r>so this should be fin<br><br>r>And we need also I2C interface to communicate with the acceleromete<br><br>r>It looks like there is everything what we nee<br><br>r>so let’s <br><br>r>back to this parts librar<br><br>r>copy manufacturer part numbe<br><br>r>go into our schemati<br><br>r>click on Librar<br><br>r>search for this microcontrolle<br><br>r>left clic<br><br>r>15 is available for JLCPCB SMT servic<br><br>r>minimum order quantity <br><br>r>Click on Plac<br><br>r>left clic<br><br>r>Escap<br><br>r>When we go back into our specificatio<br><br>r>you can see that we placed all t<br><br>r>key components into our schemati<br><br>r>Now, what we are going to do in the next ste<br><br>r>we are going to add the component<br><br>r>which are needed to support this key componen<br><br>r>and the first one is power suppl<br><br>r>Go to SMT Parts Library websit<br><br>r>All Categorie<br><br>r>we are going to search for Power Management I<br><br>r>and probably the simplest regulator is LD<br><br>r>so I’m going to click here, Dropout Regulators (LDO<br><br>r>There are many different manufacture<br><br>r>and for this kind of component I have good experience wi<br><br>r>Texas Instruments, so I’m going to select i<br><br>r>In Sto<br><br>r>a<br><br>r>we would like to use a regulator with fixed outp<br><br>r>3.3 vol<br><br>r>Appl<br><br>r>This LM1117 <br><br>r>very popular part and we have th<br><br>r>here so that’s what I’m going to us<br><br>r>It’s not maybe the best component for batte<br><br>r>powered device, b<br><br>r>it's good enough for what I nee<br><br>r>Click on Download and open datashee<br><br>r>We are going to find an example, how to connect th<br><br>r>chip, this regulato<br><br>r>I’m going to click here, System Exampl<br><br>r>and here it i<br><br>r>It is super simpl<br><br>r>just the regulator and t<br><br>r>10 microfarad capacitors, one on input and one on outpu<br><br>r>Go back to SMT Parts Librar<br><br>r>copy the manufacturer part numbe<br><br>r>go back into our schemati<br><br>r>Librar<br><br>r>Ctrl+<br><br>r>and search for the regulato<br><br>r>Left clic<br><br>r>Plac<br><br>r>left clic<br><br>r>Escap<br><br>r>We would like to place also the 10 microfarad tantalum capacitor<br><br>r>you kno<br><br>r>these capacitors from the reference schemati<br><br>r>So, in our schematic go to Librar<br><br>r>left click on Capacitor<br><br>r>left click on Tantalum Capacitor<br><br>r>once you see the list of the capacitors order <br><br>r>based on the capacitance, left click her<br><br>r>scroll down, find the 10 microfarad capacito<br><br>r>a<br><br>r>for this kind of parts f<br><br>r>passive components, very ofte<br><br>r>you can find basic part<br><br>r>So, here in this colu<br><br>r>we are going to search or look for Basic Par<br><br>r>Basic parts are usually cheaper to fit on your boar<br><br>r>Extended parts are little bit more expensiv<br><br>r>So, if they have basic part for 10 microfarad capacito<br><br>r>that’s maybe what we would like to us<br><br>r>Here it is, Basic Part, 10 microfara<br><br>r>Now, very importan<br><br>r>Hover cursor over the capacit<br><br>r>and double-check the voltag<br><br>r>You can see this capacitor is f<br><br>r>16 volts, that’s perfect, that�<br><br>r>okay for our applicatio<br><br>r>So, left clic<br><br>r>left click on Plac<br><br>r>zoom in, just use mouse whee<br><br>r>press spacebar to rotat<br><br>r>be sure the plus sign <br><br>r>on the top of the symb<br><br>r>and left clic<br><br>r>left clic<br><br>r>Escap<br><br>r>To connect these capacitor<br><br>r>we are going to use this wire featur<br><br>r>this button here in Wiring Tool<br><br>r>So, left clic<br><br>r>zoom i<br><br>r>left click, left click, left click, left clic<br><br>r>Lef<br><br>r>lef<br><br>r>left, lef<br><br>r>Escap<br><br>r>We would like to add also ground<br><br>r>so left click her<br><br>r>left click, left click, Escap<br><br>r>I will move it little bit down, ju<br><br>r>press left button, hold it down and move i<br><br>r>move i<br><br>r>And also we would like to add the power symbol<br><br>r>so left clic<br><br>r>lef<br><br>r>lef<br><br>r>Escap<br><br>r>Select this text "VCC<br><br>r>we are going to change it to "+VIN<br><br>r>because it can be, battery powe<br><br>r>it can have all the kind of different voltage<br><br>r>and left click he<br><br>r>and this is going to be the 3.3-volt outpu<br><br>r>so let’s put he<br><br>r>"+3V3", Ente<br><br>r>We still need to connect these two pin<br><br>r>So, let’s have a look into datashee<br><br>r>what they say about these pin number 1 a<br><br>r>pin number <br><br>r>I will go <br><br>r>and we are going to find the table with the pin<br><br>r>Thi<br><br>r>So, in our footprint SOT-22<br><br>r>pin number<br><br>r>is connected to groun<br><br>r>"Ground this pin for fixed output option<br><br>r>That’s exactly what we hav<br><br>r>And pin number<br><br>r>should be connected to the outpu<br><br>r>"Output voltage pin for the regulator<br><br>r>In our schemati<br><br>r>we would like to place ground symb<br><br>r>to this pin number <br><br>r>Escape, move it little bit do<br><br>r>and we would like to connect this pin number 4 with the outpu<br><br>r>Left clic<br><br>r>lef<br><br>r>lef<br><br>r>lef<br><br>r>Escap<br><br>r>To connect battery to our boar<br><br>r>we will need two through hole pins or through hole pad<br><br>r>where we will solder two wires coming from battery holde<br><br>r>And the simplest and quickest way how to add two through hole pi<br><br>r>into our board <br><br>r>to put there a simple two-pin head<br><br>r>which we will not fi<br><br>r>And that’s what we are going to do no<br><br>r>Go to Librar<br><br>r>click on Connector<br><br>r>find Pin Header & Female Heade<br><br>r>order these components based on footpri<br><br>r>a<br><br>r>notic<br><br>r>how they named the footprint<br><br>r>Maybe we could use this to find our specific componen<br><br>r>We don’t have to scroll down. We can simp<br><br>r>just write something like Header (HDR<br><br>r>Through hole (TH<br><br>r>2 pins (2P<br><br>r>pitch 2.54 (P2.5<br><br>r>and we need vertical (V) male (M<br><br>r>Search for th<br><br>r>and scroll down, fi<br><br>r>the headers which are highlighte<br><br>r>Thes<br><br>r>Left clic<br><br>r>and yeah, this could be the kind of header what we can use on our boar<br><br>r>So, just simply click on Place, left cli<br><br>r>and left click to place it into our schemati<br><br>r>Escap<br><br>r>Now, maybe we would like to flip this connecto<br><br>r>we would like to have pins on the right sid<br><br>r>so left click to selec<br><br>r>go to Forma<br><br>r>flip this symb<br><br>r>and we would like to have pin number 1 on the to<br><br>r>because that’s usually pl<br><br>r>and we would like to have pin number 2 on the botto<br><br>r>because that’s usually ground, <br><br>r>this is okay, let’s leave th<br><br>r>header like thi<br><br>r>For debugging and firmware development it can be super usefu<br><br>r>if we provide alternative power sourc<br><br>r>And the simplest way how to pow<br><br>r>this kind of simple board is use USB microconnect<br><br>r>and that’s what we are going to add nex<br><br>r>Go on SMT Parts Library websit<br><br>r>All Categorie<br><br>r>Connector<br><br>r>USB Connector<br><br>r>and let’s have a look what they have her<br><br>r>USB Type C, we don’t want USB Type <br><br>r>Micr<br><br>r>USB microconnector, this could be something what we could us<br><br>r>Copy the part number, left clic<br><br>r>go into our schemati<br><br>r>Librar<br><br>r>Ctrl+<br><br>r>search for the connecto<br><br>r>left clic<br><br>r>left clic<br><br>r>left click, Escap<br><br>r>We would like to rotate the connector, so left click to select i<br><br>r>press spacebar to rota<br><br>r>and maybe move it like thi<br><br>r>Normally, you don’t need <br><br>r>add like nothing super ext<br><br>r>around this USB microconnecto<br><br>r>but there may be some special case<br><br>r>when you would like to maybe conne<br><br>r>these D- and D+ pins through some resistor<br><br>r>If you would like to know more, you can search for something like th<br><br>r>"USB micro charging resistors<br><br>r>There are number of websites on this top<br><br>r>and usually you will find informati<br><br>r>something like thi<br><br>r>for different manufacturers and different curren<br><br>r>you may want to use different resistor values and differe<br><br>r>resistor connections between these D+ and <br><br>r>pins and the power and the groun<br><br>r>S<br><br>r>just in ca<br><br>r>you may need thi<br><br>r>what we can do, we can add some footprin<br><br>r>on our boa<br><br>r>and normally you will not fit these resistor<br><br>r>but if your special charger will requi<br><br>r>these resistors, then you may fit them late<br><br>r>Oka<br><br>r>So, that’s what we are going to do no<br><br>r>We are going to add some components around this U<br><br>r>microconnector, and we are going to connect i<br><br>r>Even we are not going to f<br><br>r>these resistors which are connected to D- and D<br><br>r>we still may want to choose resistors with values what ma<br><br>r>some sens<br><br>r>So, I will choose some of these examples which are her<br><br>r>and we will use this connecti<br><br>r>with 10k and 5.1k resistor<br><br>r>So, first we will need to find a 10k resisto<br><br>r>Go to Librar<br><br>r>be sure you have this JLCPCB Assembled selecte<br><br>r>so we only list t<br><br>r>components which can be used for the JLCPSB SMT Servic<br><br>r>and search for R04<br><br>r>10K resisto<br><br>r>Again, ideally, we would like to use a basic compone<br><br>r>so I’m going to click her<br><br>r>a<br><br>r>it looks like this first one is t<br><br>r>10k resistor what we nee<br><br>r>click on Pla<br><br>r>and just place it somewher<br><br>r>Press spacebar to rota<br><br>r>and place it like thi<br><br>r>Do exactly same for t<br><br>r>5.1k resisto<br><br>r>So, go to Librar<br><br>r>search for R04<br><br>r>5.<br><br>r>and let’s have a look if they have basic part, 5.1<br><br>r>Okay, this is exactly what we need. Left clic<br><br>r>Plac<br><br>r>and place it somewhere into schemati<br><br>r>Press spacebar to rotat<br><br>r>left click, Escap<br><br>r>We need the same resistor combination also for the second D pi<br><br>r>You know, R1 5.1, R2 10k, R3 5.1, R4 10<br><br>r>D+, D<br><br>r>So, I’m going <br><br>r>move this little bit u<br><br>r>press Ctrl hold it down, left click also here to select the<br><br>r>Ctrl+C, Ctrl+<br><br>r>left cli<br><br>r>and we can connect them togethe<br><br>r>So, left clic<br><br>r>connect these tw<br><br>r>Connect these tw<br><br>r>Escap<br><br>r>And place also ground pi<br><br>r>Escape, move it little bit dow<br><br>r>Close to this VBUS pi<br><br>r>we would like to place maybe 10 microfarad capacito<br><br>r>You kno<br><br>r>the 5 volt is coming through this VBUS pin a<br><br>r>this 10 microfarad capacitor c<br><br>r>help improve this 5 volt little bi<br><br>r>It’s not li<br><br>r>the best and super proper way how to connect USB connector, b<br><br>r>in our application it is just good enoug<br><br>r>We would like to keep it simpl<br><br>r>So, I’m going to copy this 10 microfarad, left click, Ctrl+<br><br>r>Ctrl+V and I’m going to place it maybe like her<br><br>r>Escap<br><br>r>We would like to connect the ground he<br><br>r>and we would like to connect everything togethe<br><br>r>Zoom i<br><br>r>move th<br><br>r>maybe like thi<br><br>r>connect D<br><br>r>connect D<br><br>r>connect the capacito<br><br>r>one resist<br><br>r>and also this resisto<br><br>r>Escap<br><br>r>I’m going to make some space, so I’m going to move this do<br><br>r>and all this little bit her<br><br>r>I’m going to place here the +5 USB power net symbo<br><br>r>so when we are routing the<br><br>r>tracks, then we will know it is powe<br><br>r>Just call it +5V_US<br><br>r>Ente<br><br>r>Connect i<br><br>r>and also maybe connect this shield to groun<br><br>r>so I’m going <br><br>r>draw something like thi<br><br>r>and al<br><br>r>I will connect thi<br><br>r>Escap<br><br>r>And place the ground symbols her<br><br>r>You can use this, or you can ju<br><br>r>Ctrl+C, Ctrl+V, you know, you can always select something existing a<br><br>r>do copy and past<br><br>r>We have almost connected this USB connecto<br><br>r>Only what left is this ground (GND) pi<br><br>r>that’s the simple one, but we also need to connect this ID pi<br><br>r>It can be sometimes little bit tricky, if you would like to know mor<br><br>r>you can search for something like th<br><br>r>"USB ID pi<br><br>r>and when I click for example on this lin<br><br>r>you can find the<br><br>r>information about all the kind of possibilitie<br><br>r>So, you can sometimes connect this p<br><br>r>to ground, you may leave it unconnecte<br><br>r>or you can even like put there resistors with different value<br><br>r>And the very safe way, how we can connect this p<br><br>r>is just use 0 Ohm resistor connected to grou<br><br>r>and in case you will need to experiment with this pi<br><br>r>th<br><br>r>just unfit the 0 Ohm resisto<br><br>r>leave it unfitted or you can put the<br><br>r>resistors with different value<br><br>r>Oka<br><br>r>So, in the next step, we are going to find 0 Ohm resistor a<br><br>r>we are going to connect it to this ID pi<br><br>r>I’m going to show you different wa<br><br>r>how you can maybe search for resistor<br><br>r>So, select existing on<br><br>r>copy the manufacturer part number, Ctrl+<br><br>r>go to Librar<br><br>r>and we are going to search Ctrl+<br><br>r>we are going to search based on this number, we will just change it little bi<br><br>r>So, this was 5.1<br><br>r>It mean<br><br>r>how we need to adjust this for 0 Ohm resisto<br><br>r>We need to replace this with 0 and also this one with <br><br>r>Searc<br><br>r>Okay, basic part, 0 Ohm resistor, left clic<br><br>r>left click to Plac<br><br>r>left click, Esca<br><br>r>and we can connect <br><br>r>like thi<br><br>r>And Ctrl+C, Ctrl+<br><br>r>Nex<br><br>r>we are going to connect these two power inputs togethe<br><br>r>However, we cannot just simply connect th<br><br>r>battery connector directly to th<br><br>r>5 volts coming from this USB connecto<br><br>r>Because <br><br>r>battery is connected and also the USB cable is connecte<br><br>r>USB power is connected, then they could fight togethe<br><br>r>For exampl<br><br>r>if the voltage on the battery is higher than 5 volt<br><br>r>then this this power from the batte<br><br>r>would like to go inside of th<br><br>r>power supply on the US<br><br>r>And also on the other side, if the voltage on the battery is low<br><br>r>than the 5 volt coming from the US<br><br>r>then this 5 vo<br><br>r>from the USB would try to go inside of the batter<br><br>r>And very simple way how we can prevent this fighti<br><br>r>is use diode<br><br>r>A<br><br>r>there’s actually o<br><br>r>special component which has two diodes in one footprin<br><br>r>I have used this component number of times in my previous proje<br><br>r>and that’s exactly what we are going to use also n<br><br>r>to prevent this fightin<br><br>r>S<br><br>r>let’s go inside of the Libraries, and let’s search for this special componen<br><br>r>Click on Libra<br><br>r>and search for thi<br><br>r>Left clic<br><br>r>click on Plac<br><br>r>press spacebar to rota<br><br>r>and left click to place it into our schemati<br><br>r>We are going to connect i<br><br>r>I’m going to make a little bit of spac<br><br>r>I’m going to move th<br><br>r>little bit dow<br><br>r>maybe like th<br><br>r>and also I’m going to move thi<br><br>r>I’m going to select everything around our power suppl<br><br>r>move it little bit dow<br><br>r>use the Wire button to conne<br><br>r>battery connector with the diod<br><br>r>connect USB 5 volts to dio<br><br>r>and connect it to our power suppl<br><br>r>Escap<br><br>r>I’m going to name this ne<br><br>r>so when we will be doing layout, we know this is important power n<br><br>r>I’m going to call <br><br>r>"+VBAT<br><br>r>Ente<br><br>r>I’m going to connect i<br><br>r>oka<br><br>r>And we can also connect ground symbol her<br><br>r>maybe like thi<br><br>r>Escap<br><br>r>Ctrl+C, Ctrl+<br><br>r>How th<br><br>r>special dio<br><br>r>is going to help u<br><br>r>Why we use it in this circui<br><br>r>How it is going to work, do you kno<br><br>r>A diode is a component whi<br><br>r>c<br><br>r>control how current is going to flo<br><br>r>So basically, when you have a diod<br><br>r>current can only fl<br><br>r>from this side of the diode to this other side of the diod<br><br>r>And current can’t fl<br><br>r>from this side of the diode to this side of the diod<br><br>r>It mea<br><br>r>that for examp<br><br>r>the current from this batter<br><br>r>it can vey nicely flow through this diode, which is her<br><br>r>but it can’t flow through this other diod<br><br>r>And same for the currents from this USB connecto<br><br>r>They can very nicely flow through this diod<br><br>r>but they can’t flow through this diod<br><br>r>So, by using this special component, we prevent<br><br>r>fighti<br><br>r>these two power supplies together or power sources togethe<br><br>r>When you will <br><br>r>deciding on what kind of diode to use in your applicatio<br><br>r>there are few paramete<br><br>r>what you would like to doublechec<br><br>r>so when we open datasheet of this dio<br><br>r>the important numbers or important parameters for <br><br>r>is the maximum forward curren<br><br>r>which has to be basically high<br><br>r>for as what we need for our boar<br><br>r>200 milliamps <br><br>r>high enough for what we nee<br><br>r>And also what you would like to be sure th<br><br>r>forward voltage is maybe as low as possibl<br><br>r>That’s the reason, why we use th<br><br>r>Schottky diode, because they usually ha<br><br>r>lower forward voltage, than standard diode<br><br>r>And this forward voltage <br><br>r>very important, becau<br><br>r>this is the voltage, which you will lose across the diod<br><br>r>S<br><br>r>even if we have 5 volts for example here on this USB connecto<br><br>r>you are going to use this forward voltage on this diod<br><br>r>so if it’s lik<br><br>r>I don’t kno<br><br>r>0.5 volt for 100 milliamps, then basicall<br><br>r>here on the input of our power supply, we will have not 5 volt b<br><br>r>4.5 vol<br><br>r>when we will be taking 100 milliam<br><br>r>through this diod<br><br>r>Oka<br><br>r>And there is al<br><br>r>another factor what you may want to conside<br><br>r>This voltage across the diode and the curre<br><br>r>going through this diode is going to change to powe<br><br>r>so when you multiply the voltage by the curren<br><br>r>then you will get pow<br><br>r>which is going to be changed to he<br><br>r>on this diod<br><br>r>And you would like t<br><br>r>of course you would like to be sure that th<br><br>r>heat is not too high, so your diode is not damage<br><br>r>Okay? S<br><br>r>two important number<br><br>r>forward volta<br><br>r>and the maximum forward curre<br><br>r>which you need to doublecheck if you use a dio<br><br>r>in your circui<br><br>r>We are going to make our schematic nicer, more professiona<br><br>r>I’m going to add some note<br><br>r>so place Tex<br><br>r>left click, Escap<br><br>r>select the tex<br><br>r>I’m going to change it <br><br>r>"USB (FOR POWER ONLY)<br><br>r>I’m going to change the col<br><br>r>and I’m going to make it little bit bigg<br><br>r>and maybe Itali<br><br>r>Like thi<br><br>r>And I’m going add also some text up he<br><br>r>about the battery connectors, so I’m going to copy this, Ctrl+<br><br>r>Ctrl<br><br>r>and we are going to change it maybe li<br><br>r>"BATTERY CONNECTO<br><br>r>is the text what we would like to have her<br><br>r>I’m going to squeeze this a little bi<br><br>r>so we have more space for rest of the schemati<br><br>r>By the way, it’s important how you draw this selectio<br><br>r>If you draw from the top-lef<br><br>r>then it will only select all the components which are inside of the squar<br><br>r>but if you draw this selection rectangle from bottom-righ<br><br>r>then it will select everything what is also on the ed<br><br>r>of the rectangl<br><br>r>So, this time I would like to select onlyeverything what <br><br>r>like her<br><br>r>so I’m going to move it little bit u<br><br>r>like thi<br><br>r>and same her<br><br>r>I’m going to move it may<br><br>r>little bit down like thi<br><br>r>What is also always very useful to have on your board is power LE<br><br>r>so go inside of Librar<br><br>r>we are going to fi<br><br>r>"0805 LE<br><br>r>maybe green colo<br><br>r>search for i<br><br>r>And be sure we are going to use a basic par<br><br>r>so this first one is okay, left clic<br><br>r>left click on Plac<br><br>r>press spacebar to rota<br><br>r>and put it inside of our schematic maybe somewhere like thi<br><br>r>Escap<br><br>r>When you place an LED into your schemati<br><br>r>then, together with LE<br><br>r>usually you also need to place a resisto<br><br>r>Because this resistor will lim<br><br>r>the maximum current which will flow through this LE<br><br>r>Okay? You cannot fl<br><br>r>very high current through LED because you will damage this LE<br><br>r>And little bit later I will show you, how you can calculate th<br><br>r>minimum value of the resist<br><br>r>which you may need to use with LE<br><br>r>but for this power L<br><br>r>when I calculated this minimum value of the resisto<br><br>r>the LED was like super bright, it w<br><br>r>disturbi<br><br>r>and it mea<br><br>r>what I had to do, <br><br>r>I had to actually try different valu<br><br>r>different resistor value<br><br>r>I just desolder<br><br>r>one resistor and placed different o<br><br>r>and I found out that when we use 10k resist<br><br>r>together with this LED, then the brightness of the LED is just righ<br><br>r>And that’s what we are going to use in the schemati<br><br>r>we are going to place 10k resist<br><br>r>to limit the current which will flow through this LE<br><br>r>It’s going to be super simpl<br><br>r>because we already have 10k resistor in our schemati<br><br>r>We can just select it, left clic<br><br>r>Ctrl+C, Ctrl<br><br>r>and left click to place i<br><br>r>Connect the resistor to the powe<br><br>r>connect resistor to the L<br><br>r>a<br><br>r>copy the ground symbol, Ctrl+C, Ctrl+<br><br>r>connect it to the L<br><br>r>and maybe move it little bit down like thi<br><br>r>Don’t forg<br><br>r>the currents through a dio<br><br>r>can only flow one directio<br><br>r>So, if your LED is rotated like thi<br><br>r>it’s not going to wor<br><br>r>Okay? It has to be rotated like thi<br><br>r>because current only can flow from this side of dio<br><br>r>to this other side of the diod<br><br>r>No<br><br>r>a tricky questio<br><br>r>Do you know why we connected this power L<br><br>r>to this +V_US<br><br>r>We could connect it to +VB<br><br>r>or even bette<br><br>r>We could connect it to this +VI<br><br>r>And then, power LED would be always <br><br>r>when our board would be powere<br><br>r>Howeve<br><br>r>when you are using batte<br><br>r>to power up your boar<br><br>r>maybe you really don’t want to was<br><br>r>the energy from the batter<br><br>r>to light up this power LE<br><br>r>And that’s the reason why it is connect<br><br>r>only to this +V_USB, becau<br><br>r>in this case, the power LED will on<br><br>r>turn on when your board is powered from US<br><br>r>but it’s going to stay of<br><br>r>it’s not going to consume any ener<br><br>r>when your board is powered from batter<br><br>r>So, we place it here to sa<br><br>r>the power from the batter<br><br>r>We have finished our power circui<br><br>r>we are going to make few small adjustments or tweak<br><br>r>I’m going to make it little bit nicer, <br><br>r>it looks symmetrica<br><br>r>We would like to maybe a<br><br>r>some notes that these resistors are not going to be fitte<br><br>r>I’m going to copy this, Ctrl+<br><br>r>Ctrl+<br><br>r>I will change the text to "NF" like not fitt<br><br>r>and I don’t want to make it <br><br>r>visible, maybe u<br><br>r>this kind <br><br>r>grey color, oka<br><br>r>Ctrl+C, Ctrl+<br><br>r>Ctrl+<br><br>r>Ctrl+<br><br>r>Oka<br><br>r>I’m going to add a titl<br><br>r>Ctrl+C, Ctrl+<br><br>r>Let’s call it "POWE<br><br>r>and make it little bit bigge<br><br>r>Use bol<br><br>r>no itali<br><br>r>Oka<br><br>r>A<br><br>r>maybe move it little bit dow<br><br>r>Perfec<br><br>r>Nex<br><br>r>we are going to connect this L<br><br>r>and to limit current<br><br>r>flowing through these LED<br><br>r>we need to put here some resistor<br><br>r>And as I promise<br><br>r>we are going to lea<br><br>r>how to calculate value of these resisto<br><br>r>which we would like to use together with an LE<br><br>r>Select our LE<br><br>r>we would like to see the datashe<br><br>r>so left click on View Datashee<br><br>r>open datashe<br><br>r>and the numbe<br><br>r>which are important for us a<br><br>r>forward curre<br><br>r>and forward voltag<br><br>r>When we have a closer look at like very simp<br><br>r>circuit, how an LED is connecte<br><br>r>it is going to look like thi<br><br>r>There is some powe<br><br>r>then we have a resistor and the LE<br><br>r>Now, the voltage across the LED, we know this voltag<br><br>r>This is t<br><br>r>forward voltage which we can see here, and it is different f<br><br>r>different LED colo<br><br>r>The voltage which is going to be across this resist<br><br>r>is basically the power voltage – the voltage on this L<br><br>br>And biggest voltage on this resis<br><br>br>will be here when…<br><br>Do you know w<br><br><br>When this voltage across LED is going to be the low<br><br><br>So, from these three numb<br><br><br>the most important for us is this low<br><br><br>2.1 volt num<br><br><br>That’s what we would l<br><br><br>that’s what we would like to use in our calculat<br><br><br>Then also this forward current 10 milli<br><br><br>is important for our calculat<br><br><br>So, remember these two numb<br><br><br>2.1 volt and 10 millia<br><br><br>Let’s go back to our simple cir<br><br><br>and I’m going to en<br><br><br>this next l<br><br><br>which is telling us what we already k<br><br><br>O<br><br><br>So, this is the voltage across the diode, 2.1 v<br><br><br>and this is showing the cur<br><br><br>0.01 amps or 10 milli<br><br><br>which we would like to have flo<br><br><br>through our circuit, through our resistor and through our di<br><br><br>As I already explai<br><br><br>to calculate the vol<br><br><br>across this resistor is very sim<br><br><br>Basica<br><br><br>it is the input voltage – the voltage on the d<br><br>><br>And in our <br><br>><br>the input vo<br><br>><br>can be 5 x 1.5 volt, thes<br><br>><br>five 1.5 volt batte<br><br>><br>And – 2.1 volt which is across the <br><br>r><br>it means the maximum v<br><br>r><br>which we will have in our circuit across this re<br><br>r><br>is going to be 5.4<br><br>r><br>Once we know this voltage across this res<br><br>r><br>and we also know the current which should flow through this res<br><br>r><br>we can very simply calculate the value of this res<br><br>r><br>We can use this equat<br><br>r><br>Ohm�<br><br>r><br>which says that the resistor<br><br>r><br>equals the voltage divided by cu<br><br>r><br>so in our case it would be 5.4 volt / 0.<br><br>r><br>and our minimum resistor which we can use together with our<br><br>r><br>is 540<br><br>r><br>So, this <br><br>r><br>super simple way, how you can approximately calc<br><br>r><br>what is the minimum value of the res<br><br>r><br>which you need to connect together with a<br><br>r><br>Based on this calculated <br><br>r><br>we would like to find our res<br><br>r><br>So, what you can do, you can sear<br><br>r><br>somethin<br><br>r><br>"resistor va<br><br>r><br>I’m going to click on this <br><br>r><br>and in this table you c<br><br>r><br>the basic st<br><br>r><br>resistors what you can normall<br><br>r><br>And in our case, we would like to use the c<br><br>r><br>resistor with higher value than what we have calcu<br><br>r><br>So, we calculated 54<br><br>r><br>and the closest higher standard re<br><br>r><br>is 560<br><br>r><br>So, this is the resistor what we are going to add into our sche<br><br>r><br>We are going to use same tec<br><br>r><br>as we used when we were looking for 0 Ohm res<br><br>r><br>I’m going to select an existing res<br><br>r><br>I’m going to copy manufacturer part number, C<br><br>r><br>go to Li<br><br>r><br>clear<br><br>r><br><br><br>r><br>and we are going to adjust this n<br><br>r><br>change it to 560 Ohms (<br><br>r><br>s<br><br>r><br>Okay, this is 560 Ohm res<br><br>r><br>it is extended pa<br><br>r><br>it’s<br><br>r><br>We need this one for ou<br><br>r><br>so select it, left<br><br>r><br>and place it into our sche<br><br>r><br>Left <br><br>r><br>zo<br><br>r><br>[https://www.ourmidland.com/search/?action=search&firstRequest=1&searchindex=solr&query=press%20spacebar press spacebar] to <br><br>r><br>and place it maybe like<br><br>r><b<br><br>r><br>and<br><br>r><br>E<br><br>r><br>When you would like to connect something in your sche<br><br>r><br>you don’t have to always use this wiring<br><br>r><br>you can simply just click o<br><br>r><br>pin which is<br><br>r><br>and you can just start drawing the<br><br>r><br>It is little bit faster,<br><br>r><br<br><br>r><br>One of the most common<br><br>r><br>how to contro<br><br>r><br>is to use a transistor, which is connected betwee<br><br>r><br>LED and resistor and the g<br><br>r><br>And the, probably the most common transistor what i<br><br>r><br>for this purp<br><br>r><br>2N7002 trans<br><br>r><br>So, go into our Li<br><br>r><br>and search for 2<br><br>r><br>As you can see this is the basic part, so just left <br><br>r><br>click on <br><br>r><br>zo<br><br>r><br>place it<br><br>r><br>then we need also another on<br><br>r><br>and the third on<br><br>r><br>here. E<br><br>r><br>Connec<br><br>r><br>together with the res<br><br>r><br>E<br><br>r><br>And we need to connect these transistors also to ground, s<br><br>r><br>ground symbol, Ctrl+C, C<br><br>r><br>C<br><br>r><br><br><br>r><br>and conne<br><br>r><br>I’m going to make it a little bit <br><br>r><br>I’m going to move this litt<br><br>r><br>away from each other, so there is little bit more <br><br>r><br>I’m going to select<br><br>r><br>press Ctrl, hold it down, select also the tran<br><br>r><br>and just mo<br><br>r><br>And same<br><br>r><br>select<br><br>r><br>press Ctrl, hold it down, select also the tran<br><br>r><br>and move it like<br><br>r><br>I’m going to draw short lines, which will be connected to<br><br>r><br>gates of the transi<br><br>r><br>and then we will name these<br><br>r><br>or these connec<br><br>r><br>To name them, we would like to see which of these LEDs i<br><br>r><br>which is blue, and which is <br><br>r><br>so sele<br><br>r><br>Edit <br><br>r><br>and show these nu<br><br>r><br>So<br><br>r><b<br><br>r><br>ye<br><br>r><br>This is pin number 2,<br><br>r><br>When we go into dat<br><br>r><br>of th<br><br>r><br>we can see pin number 2 i<br><br>r><br><br>r><br>this is the re<br><br>r><br>and we would like to nam<br><br>r><br>mayb<br><br>r><br>"L<br><br>r><br>Pin numbe<br><br>r><br>blu<br><br>r><br>so click on this Net <br><br>r><br>left click here, E<br><br>r><br>left click to sel<br><br>r><br>and change<br><br>r><br>"LED_B", <br><br>r><br>And the last one, pin number 4 w<br><br>r><br>the gree<br><br>r><br>so again what you can do you can click here, or you can simply just copy<br><br>r><br>Ctrl+C, <br><br>r><br>and cha<br><br>r><br>to <br><br>r><br>Select the LED, Edit Symbol and hide<br><br>r><br>names or numbers <br><br>r><br>because they don’t look very nice in the s<br><br>r><<br><br>r><b<br><br>r><br>my question to <br><br>r><br>where to connect this pin of th<br><br>r><br>Do you<br><br>r><br>We could connect it to the battery v<br><br>r><br>or this USB v<br><br>r><br>or t<br><br>r><br>or 3.3 <br><br>r><br>What would be the best way to connect<br><br>r><br>We don’t want to connect it to the battery or the USB, because<br><br>r><br>it would only work when the battery would be con<br><br>r><br>or when the USB power would be conn<br><br>r><br>So, we could connect it to +VIN o<br><br>r><<br><br>r><br>there are two reasons why we don’t want to use 3.3 <br><br>r><br>The first <br><br>r><br>that it can be quite low vo<br><br>r><br>If you re<br><br>r><br>the forward voltage for thes<br><br>r><br><br>r><br>2.1, 3.1 and 3.0<br><br>r><br>so this means that this green LED, it ma<br><br>r><br>at least 3.1 volt to be able to<br><br>r><br>So, 3.3 volt as a power supply may not be the best <br><br>r><br>and<br><br>r><br>we really don’t want to drive high currents through thi<br><br>r><br>because on this LDO, there will be some l<br><br>r><<br><br>r><br>and the losses, it means we would just<br><br>r><br>energy from the ba<br><br>r><br>So, maybe the best way to connect o<br><br>r><br>is use this<br><br>r><br>And that’s where I’m going to conn<br><br>r><br>or that’s where we are going to conne<br><br>r><br>Left click on this +VIN s<br><br>r><br>Ctrl+C, C<br><br>r><br>place it here and conne<br><br>r><br>Where we have a look on<br><br>r><br>our finished LED conne<br><br>r><br>you may notice it is little bit differen<br><br>r><br>what we calculated<br><br>r><br>Okay? This is like super simple conne<br><br>r><br>Just power, resistor an<br><br>r><br>In our <br><br>r><br>the power goes through this <br><br>r><br>there will be some loss like I don’t know 0.5<br><br>r><br>Then it also goes through<br><br>r><br>transistors, there may b<br><br>r><br>voltage loss across these transi<br><br>r><br>but our calculation is still good enou<br><br>r><br>to use the values of the resistor what we have calcu<br><br>r><br>The currents are not going to be h<br><br>r><br>They will be actually, in this real ci<br><br>r><br>they may be actually little bit <br><br>r><br>because the final voltage across the diode plus re<br><br>r><br>may be little bit<br><br>r><br>than this 7.<br><br>r><br>what we use for the calculation as the power input from these batt<br><br>r><br<br><br>r><br>I just wanted to point out this<br><br>r><br>even we use like super simple calculation, this calculat<br><br>r><br>still like good <br><br>r><br>for what we n<br><br>r><br>good enough to calculate the resistor<br><br>r><br>for thi<br><br>r><b<br><br>r><br>you may be asking<br><br>r><br>why we had to use these trans<br><br>r><br>to control these<br><br>r><br>Could we maybe connect these LEDs directly with our microcontr<br><br>r><br>In some cases<br><br>r><br>you can control LED directl<br><br>r><br>the pins of the microcontr<br><br>r><<br><br>r><br>you need to know, what you are <br><br>r><br<br><br>r><br>And anyway, if, even if you know what you are <br><br>r><br>as you ca<br><br>r><br>even I have used i<br><br>r><br>our schematic, this kind of connection, because t<br><br>r><br>much more sta<br><br>r><br>and this kind of connection is much <br><br>r><<br><br>r><br>it is the easies<br><br>r><br>how you can control all the kind of components or d<br><br>r><br>which may require even higher cu<br><br>r><br>than what you can drive with directly, with microcontroller di<br><br>r><br>and<br><br>r><br>when you use these transi<br><br>r><br>then you can basically power up<br><br>r><br>devices or components from all the kind of different p<br><br>r><br>and you don’t really need to<br><br>r><br>if this power is going to influence somehow your microcontroller o<br><br>r><br<br><br>r><br>So, this kind of connection is much <br><br>r><br>and I use it<br><br>r><br>to control something or an<br><br>r><br>through the pins of the microcontroll<br><br>r><br>almost always, use these transi<br><br>r><br>Even when I drive<br><br>r><br>I’m going to open datasheet of this trans<br><br>r><br>left click, View Data<br><br>r><br>open data<br><br>r><br>and we are going to have a look, how this transistor <br><br>r><br>So, I’m going to copy this "MOSFET (N-Chan<br><br>r><br>that’s what we are using, C<br><br>r><br>and I’m going to <br><br>r><<br><br>r><br>something like this and may<br><br>r><br>"switch simula<br><br>r><br>When I scroll little bit<br><br>r><br>here left <br><br>r><b<br><br>r><br>this is a very nice article, where y<br><br>r><br>learn, how the transistor is going to<br><br>r><br>but basi<br><br>r><br>whe<br><br>r><br>when the gate of our transistor is going to be connected<br><br>r><br>then the transistor itsel<br><br>r><br>behave as a open s<br><br>r><br>So, basi<br><br>r><br>when this is going to be 0 it<br><br>r><br>this LED is not connected to g<br><br>r><br>Ho<br><br>r><br>if you connect the gate of the transistor to <br><br>r><br>then this transistor is going<br><br>r><br>like closed s<br><br>r><br>so in our<br><br>r><br>when we connect <br><br>r><br>for example when the microcontroller set output to<br><br>r><br>then this transistor wil<br><br>r><br>and it will make conn<br><br>r><br>between this resistor and the g<br><br>r><br>so it means the current will flow through our LED and it will switch o<br><br>r><br>Okay? If you would like to know more, then you can rea<br><br>r><br>whole ar<br><br>r><br>If you would like to choose your own transistor for your own <br><br>r><br>there are couple of numbers which are impo<br><br>r><br>So, when we g<br><br>r><br>datasheet of the trans<br><br>r><br>this is what you may n<br><br>r><br>double <br><br>r><br>So, <br><br>r><br>you would like to know what is going to be the maximum c<br><br>r><br>which can flow through your trans<br><br>r><br>Okay? In this case,<br><br>r><br>0.115 am<br><br>r><br>115 mill<br><br>r><br>It is enough for our applic<br><br>r><br>The maximum voltage between D and S is 60 <br><br>r><br>we have like 7.5 volt, that’s<br><br>r><br>Maximum Gate-Source voltage +- 20 volts, th<br><br>r><br>the voltage what you can put on the<br><br>r><br>But what is more important is this Gate-Thre<br><br>r><br>This is basically the voltage what you need to<br><br>r><br>on this gate to open the trans<br><br>r><br>so it i<br><br>r><br>2.5 volt, we will be using 3.3 volt, that, it’s<br><br>r><br>And also Drain-Source On-Resis<br><br>r><br>This is the resis<br><br>r><br>which you will have between D and S when your transistor is<br><br>r><br>And this resistance it depends on the voltage which you apply on the<br><br>r><br>so for example if on the gate there is like 5<br><br>r><br>then the resistance i<br><br>r><br>transistor can be like as h<br><br>r><br>7 Ohms, so this could be then like 7 Ohm res<br><br>r><br>Okay? So, these are the n<br><br>r><br>which you may want to doubl<br><br>r><br>when you will be using your own transistor in your own boards.