Tutorial 03 for Arduino: Electrical Engineering Basics

[@XRugZaK]

7:06 when the button is not depressed, the resister pulls it down... what a great friend that resistor

[@MrGhostDLM]

hhhhhhhhhhhh

[@shutdahellup69420]

XRugZaK lol

[@chemicalcrib9708]

lol

[@wanderingcameraguy]

I first saw this video when i was in school. 11 years later, I'm a Robotics Engineer. Thank's Jermy for introducing me to Arduino.

[@mr.kapasi1513]

Amazing man. Please share your journey with us Any tips for beginners who are pursuing robotics?

[@sciguy14]

@samsfilm So glad I could help! Let me know if there are any other electronics concepts that you are unclear on.

[@MohdHasan-mh7cl]

Jeremy you are awesome...I am NOT totally blank about electronics...I am a hobbiyst and keep trying to learn about the subject...your tutorials are absolutely awesome...this is exactly what I have been looking out for long -> understanding some basic fundamentals (without going too deep to the level of electrons, ha ha) and getting started with microcontrollers...Thumps up buddy..Thank you so much and thanks to element14 as well.

[@sciguy14]

Yes, slightly. But you also need the pulldown effect to be strong enough to change the value of the IO pin.

[@sciguy14]

@raghunitin The general rule is to go by the datasheet. The manufacturer will always suggest values to use with their various components. If you look up the datasheet for your voltage regulator, you'll see what I'm talking about. The ideal value will strike a balance between removing noise, and not impacting response times.

[@sciguy14]

@glennlopez There is a relatively complex derivation that goes into calculating this value based on the input pin impedance and a few other characteristics of the microcontroller you are using. This information is generally given in the microcontroller datasheet. The atmega 328, which is on the arduino, specifies that 10k is the the ideal value for this chip.

[@jeriellsworth]

Thanks for the shout out! Keep up the great videos.

[@PyroBrit]

Thank you for taking the time to put these videos together. The section on pull down resistors was extremely useful to me and has explained quite clearly why I need them. I used the led PWM (with button) circuit from your 2nd video that has a pull down resistor as an example. Disconnect that pull down and the PWM button has a mind of its own.

[@sciguy14]

@pgheit011 Yes, for an ordinary diode, the forward voltage drop is .6V, but the typical voltage drop for a light emitting diode is around 2.0V.

[@sciguy14]

@Ayabrego EE is what you make of it. You can be an analog designer and do zero programming, you can do exclusively digital work, which is a lot of programming (though it's fun programming in my opinion), or you can do mixed signal design which is somewhere in the middle. I'm do mostly mixed signal stuff, though I focus more heavily on the digital side.

[@sciguy14]

@claymantoo 10K is a pretty standard value. "Stronger" pulldowns are lower valued. What you choose depends upon the impedance of the pin you are pulling down.

[@MattWolfgang]

This was a very helpful tutorial. I've already worked my way through one Arduino book, and I'm a hundred pages into another one, and while Ohm's law was explained in both of them, neither did a good job of explaining pull down resistors or why it was necessary to use the resistor with a pot/sensor. It was more like here's the circuit, and now I'll explain the code. This tutorial really clarified things for me.

[@reedfranklin8635]

2 yrs old and these videos are great, my 12 year old and I are learning together while working through your videos

[@sciguy14]

@1AppleMaker yes, 2V drops across the LED, which leaves 3V to drop across the resistor.

[@biggerbrother7]

Jeremy, You are a brilliant teacher. No doubt, companies all around the country are going to want hire you on their team.

[@james9012]

It's so difficult to find great tutorials like these, thanks man!

[@sciguy14]

@raghunitin I already filmed the next two episodes. What is your question about about capacitors? Wikipedia is a great resource, and so is hyperphysics.

[@sciguy14]

@Hoowtoall @danbgtc Is correct. Also, don't forget that older videos have been online longer, so it makes sense that they would have more views.

[@sciguy14]

@iranianfrog It's in the parts list available for download from my website (link in the description). This is my biggest one, I also have about a dozen breadboards of various smaller sizes.

[@draytonPW]

You are really helping to make sense of a lot of things I have been struggling to understand. And I have watched many other videos. You are a truly gifted teacher and I am not just saying that. Thanks! Liked and subscribed!

[@sciguy14]

@BanthaFodd3r You generally just reference the datasheet. It has to do with cutting out certain frequencies.

[@laragrimes855]

I've looked back through all the comments and I'm like many other viewers. This is a video about electrical engineering. You explain everything wonderfully about resistance then just throw in decoupling capacitors without ever explaining how you choose the values for them. PLEASE: What is the electrical engineering behind choosing the decoupling capacitors? Love the videos. Learning a lot. Please answer this question. Thanks.

[@putinscat1208]

Larry Grimes He probably used the recommended values from the datasheet of the particular regulator.There are many types of regulator circuits that supply 5V, so his capacitor values might not work in your case. A good source of 5V is a USB power plug for changing phones, and that's what I would use.

[@asifa.993]

+Larry “Dr. G” Grimes Those are the required capacitance values as per the manufacturer's data sheet . You can go for different values , but sticking to these precise values will give you higher efficient output , i.e a stable DC 5V.

[@generalgeek314]

I love your tutorials! I just got an Arduino today and have a basic understanding of programming and electronics, and your videos helped a ton!

[@kesavanrangan]

Awesome video... By the way, I have a question: when you are calculating the resistance connected with the LED to avoid drawing much current, why did you calculate using the dropped down voltage of 3V? Ain't the resistor connect just before the LED, which means we have to consider 5V...

[@realulli]

Let me try to explain. Imagine, you have a stream. You build a dam. The water level rises to a height of 5V until is overflows somewhere else. You drill a small hole in the bottom that lets enough water pass to drive your mill. Unfortunately, the wheel of the mill is 2V tall, so you need to add another small dam that will raise the water level back up to 2V. Now, the water pressure behind the big dam is not enough to push enough water through the small hole to make your mill run properly, so you need to enlargen the hole. The hole needs to be large enough to work as if the big dam were only 3V tall. Now the metapher kinda breaks down - all the water down that stream has to go through the mill, so just removing the 5V tall dam won't work, since then you'd get only a 2V drop and an awful amount of water would wash your mill away. The LED is that mill, the small hole is the resistor. If you had a 2V power supply, you'd have to balance the voltage and current rather precisely, otherwise your LED would still burn out... Does that make things clearer?

[@viktoriomilanov5375]

@@realulli yep man thanks for putting in time for this answer ^^

[@sciguy14]

@karolis4ever What does what do? The arduino? It's a microcontroller, you make it do whatever you want.

[@stuartblaber7227]

Although in most cases it can be ignored, for critical circuits, like measuring, the resistance of the battery must be included in the ohms law calculations. The battery resistance can be calculated using a precision resistor in the load and measuring the voltage across it.

[@MrPanolvios]

My friend your lesson is perfect. I am a teacher of electrical engineering in Technical school in Greece... Thanks a loooooooooooooooooooot!!!

[@abstraktlighting]

hi, Can you tell me how you got to the conclusion that 2v olts drop over the led ? Did I miss something?

[@artl52]

i would like to know that also. It wasn't obvious, at least to me!

[@iwasaccusedofpuddi]

+Arthur - Jake - Leyenberger in case this has stumped anyone else, one finds the voltage drop with V = I * R (same formula to find the supply voltage).Voltage drop = Resistor with 100 Ohms * the current of 20 mA => 2V --> (100 * .020 = 2)

[@commodorekitty]

abstrakt lighting You might already have found an answer, but you can look it up on the LED's data sheet. Look for Vf (forward voltage).

[@haniefknight]

although i've already knew about this basic, but this guy is explaining with different perspective with a wide range of knowledge. It feels good when we learn and start from the begining again. , 2021

[@jorgewashington2981]

Another excellent video. Loved how you included a practical application. That helps a great deal when learning electronics. You are a natural teacher young man. Keep up the good work. Thank you so much.

[@samsfilm]

This was brilliant. Made everything so clear. I can program without an issue, but getting my head round the electronic side was killing me. Thanks!

[@sciguy14]

@jimmyjampola Let me know if you have any questions about the coding. I have the code from each episode available for download from my website with comments (link in description). Really glad you're enjoying the videos.

[@1972hattrick]

It is a 3 pin package. Inside the package it has transistors and zener diodes hooked up in such a way that it doesn't matter what voltage you apply to the circuit it will output the voltage it was designed for. You must supply a proper voltage within a range say 4V - 24V and it will output 9V etc. It uses zener diodes bc they drop more than 0.7V and they are designed to drop a specific voltage no matter what. Hope that helps.

[@whisk0r]

Great job, Jeremy! The screen cap overlays worked really well (even if they were a pain to get).

[@GretoDaBoss]

Arduino Starter here, I love your videos. Keep up the good work

[@srkshpdmnbhn]

True that further zooming would help, but come on, he is doing so much in the best-est way. I wont complain, hats off to Jeremy.

[@TonyTheTrain]

Man, this is some good stuff. Thank you so much for these videos. You're answering questions I didn't even know I had to help me build circuits.

[@jenmanzella7026]

YOU'RE WEARING A DOCTOR WHO SHIRT!!! Okay... I liked your videos before but now have 10x more respect

[@YouGenom]

This is perfect bridge between simple electric circuits knowledge and electronic engineering! Thanks a lot!

[@canadiandude7]

Hey there, I know these are old but I'd like to thank you for producing a tutorial with substance. Appreciate it!

[@ScubaStevo83858]

Best teacher of Arduino I have watched. I finally sorta get it! Thanks, Jeremy!

[@virgilmachine2504]

Thank you Jeremy. I got a little confused by the Voltage Regulator piece. The concept made sense, but it took me a bit to figure our what you were doing on the breadboard (I'm new to circuits, and to breadboards). I did some reading on breadboards, and watched the segment a couple of times, then it became clear--the battery was connected to the + and - rails, the .1uF capacitor on the same rails, then the Voltage regulator with + pin on top, with a jumper to the + rail from that row, the ground pin in the middle with a jumper from that row to the - rail. The jumper from the 5V pin row (which goes to the multimeter) came before the 22uF capacitor, which is has one pin on that row and one to ground. Another jumper from ground goes to the meter. I'm just writing this out to see if I can articulate, and perhaps save someone some time if they hit the same ignorance block that I did. This was fun and educational.

[@darac1]

You're awesome. You have explained everything i was googling around for the past two days. Thank you! Your tutorials are great, so keep up the good work!

[@baba_tj6352]

You know a thing?? Let it I am gonna tell you! You are a very good teacher.. Perfection on every word and each concept...

[@henriquesglima]

Your tutorials are great!!! Congratulations and Thanks so much for sharing your knowledge! I just bought my arduino board and will start going all your videos!!!

[@electronash]

There's the 5V label and the Ground symbol. These essentially form the circuit from the power supply / battery. The important thing is, the output voltage pin from a voltage divider / potentiometer wiper is generally "relative to Ground". It's often good to think of voltage as the "potential difference" between the two measured points rather than just a circuit. So, if you have +5V, Ground, and -5V, there would be 5 Volts between Ground and +5V, but 10 Volts between -5V and +5V. :)

[@arnthorsnaer]

thank you for these tutorials, your way of structuring this topic and your pacing really works for me

[@RadRider33]

@rainbowsalads Yes it would. Depending on whether or not the diode is closed (infinite resistance) when it is exposed to light or when it's dark, changing its location with the resistor will "reverse" when the divider has voltage or not.

[@motopest]

Yup! My kids are learning better with your help than I can do on my own. I hope the best for you, man!

[@electronash]

"COM23" is just his serial port number (for the Arduino's USB serial). The Java window you can see is just the "Serial Monitor" part of the Arduino software. (Tools > Serial Monitor, or Ctrl-Shift-M). This lets you see the serial output from the Arduino if you're using the built-in serial functions. Serial.begin(9600); Serial.println("Hello world!"); You just need to download the s/w from the Arduino site, plug in and install the USB serial driver, then choose the correct port in the s/w.

[@manutube8080]

Jeremy great video, hope to see more. It will be very interesting to have on the yellow difficulty level led some projects like the 3D led box or some Color organ made with the arduino.

[@hankhamner3671]

You have a great gift for teaching. Thank you very much for taking you time to help us understand electronics and Arduino.

[@BanthaFodd3r]

Great tutorials, Jeremy! Could you explain how the values of the decoupling capacitors are chosen?

[@prinspatrick1571]

Best tutorial on using Arduino and learning Electronics if found! Thank you very much!!

[@JamesBos]

These video's are fantastic mate! I'm absolutely loving it, if I only had one wish, it would be go into a little bit more detail about some of the programming side of things for people like me who aren't too code savvy. You've got me inspired! In terms of the code side of it, I've been going back and forth between your vids and the arduino dot cc page to make sense of some of the code. Keep it up mate!

[@sciguy14]

@francisroan 20mA = .020A, so 3V/.020A = 150 ohms

[@sciguy14]

@whisk0r Getting them was fine. For some reason - They were giving me all kinds of issues when I was editing them... Luckily, I was able to use my 1337 haxs to fix it.

[@kevinrhug]

Again your rate/pace is perfect. If someone needs it slowed down they could always pause and if they need to to repeat they can rewind. I can't tell you how grateful I am for these. We are going to experiment with making a makeshift flex sensor with a piece of transparency film. I made one by sanding one side and coloring on the sanded portion with a graphite pencil. If it is not too much trouble could you direct me to a video of yours where you talk about these? I want to map the range of resistances that we get to a range that we can use to drive a servo.

[@marksneighbour]

So are all the pins connected to ground, because at around 5:27 the circuit starts at 5 volts but it isn't connected to ground, instead it's connected to a pin. Wouldn't that just be an incomplete circuit?

[@vectorcalculator7313]

dcfan101 The should be. Pin 8 here is used as an input, so it reads the voltage it receives: when pressed, the current flows from the 5V to pin 8, which, if connected to ground, therefore reads a deltaV of 5V, or 1 (in digital values).

[@CartecayRiver]

Thank you Jeremy, great video, however I did see something that was probably just an oversight, but to make everything reun and work more effectively, your filter capacitor (the large one) needs to be on the input to the voltage regulator, where the source needs it, and the decoupling capacitor (the 0.1uF), should be on the output to decouple the noise. It would not hurt to also put, say a 10uF, or so on the output also. Thank you for making this video available, My weakness is in programming.

[@sciguy14]

@jimmyjampola Ah of course! Yeah, the ardunio function reference is awesome, and they give tons of examples.

[@sciguy14]

No, current is defined as flowing from positive to negative. electrons flow flow the opposite of the direction in which we define current - they are what flows from negative to positive.

[@Tigerskunk]

For electricity it will always use the path of less resistance. Even a 5K resistor is less resistance than the air. The pull down resister also "shows" what is considered the ground or the lower voltage level. You could also build circuits that instead of having 0V up to 5v, that use say 5v as low and 10v as high. Using the pull down helps give a base for the voltage readings to start from. Where no pull down would leave a "floating" point of reference for the circuit to read from.

[@gavin4785c]

Man, thank you for these. Your Arduino vids are explained and ordered so nicely!!

[@crocellian2972]

You did well making this understandable. You can sped a decade on this topic when you introduce AC.

[@oadka]

It is a great video.This series has helped to learn about Arduino .Thank You Jeremy Blum.

[@oldaccount847]

In response to Brett Roe, the m that you are referring to is actually not an m, but the greek letter mu. It is also called micro when speaking in units such as farads, volts or amperes.

[@ramili0711]

Your videos are absolutley awesome, I'm a junior ece major in UIUC, and besides textbook I don't know anything else from my major. I kind of have problems with some of the programming part, like functions, or how to creat libraries ... I never get to learn a language from basic, I just know different things from different languages. Do you have any suggestions for learning C language?

[@sankeelchavan6150]

7:28 what happens if we connect the circuit to ground without a resistor?

[@jemodevera1241]

Jeremy i like the way how you explain the led changed to yellow light instead of green (as expected) due to over current (unbias) flowing into it. are you an Engineer?

[@sciguy14]

@Shockszzbyyous Sounds like you have your button configured with a pullup.

[@electronash]

You'll also see around 6:22 that the logic level on the pin stays HIGH even after the button is released because there is some capacitance in the chip / circuit which holds a tiny charge (and due to the chip's topology etc.). The pull-down makes sure that charge drains to Ground when the button is released. Who would have thought hooking up a simple button would be so much trouble. lol There are lots of factors to consider, but it's not too tricky once you wrap your brain around it. :)

[@iruruley]

Great videos!! Thanks! I have a question about the voltage regulator. I bought a L7806CV regulator and its Data Sheet says I should use 0.33uf (V input) and 0.1uf (V output) instead of 0.1uf and 22uf. What is the difference? Can I use the capacitors in the video anyway?

[@SuperJT1974]

Great video again - Thanks. I would like to know how you came up with 0.1microF, and 22 microF as the decoupling capacitor values. I understand it has something to do with noise that could be expected in each part of the circuit, but have no idea on practically choosing/working out these required values. Many thanks.

[@funky7281]

Awesome tutorial Jeremy. What power supply are you using to get 12v or 5v line on the breadboard ? Could anyone please suggest any links to buy good reliable power supply ? I checked on Amazon and wasn't sure which one was good.

[@AlexBoltonKing]

Just a quick question regarding the decoupling capacitors.. how do you know which ones to go for? is there an equation to calculate what you should be using? Thanks, Alex

[@JPEE2009]

It doesn't have to have 5 Volt to change the logic. It could be around the TTL value of 2.6 - 5 volts. Static or even magnetic fields around the wire can create voltage. Static alone can be in hundreds or thousands of volts for a split second. If you use a pull-down, current will flow to the least resistance path (reason for lighting rods on building..etc), therefore, any voltage on that wire will go straight to ground and not to the pin.

[@pak715]

On he voltage regulator. Can you tell us the formula to figure out which decoupling capacitors to use ? You have a .1 on the input side and a 22 on the output side.

[@electronash]

Oh, also, most microcontrollers have an internal pull-up option... So, if you set the pin as an INPUT, but still "set" the pin HIGH, it will enable the internal pull-up for that pin. Then all you need to do is connect your button between the pin and Ground. On the Arduino s/w, you just do this... pinMode(pin, INPUT); // set pin to input digitalWrite(pin, HIGH); // turn on pullup resistors I've found that this quite prone to noise though, so best to go with a real resistor.

[@edwardmabbott3612]

So question. The last part of the video with the Regulators. Are you saying if 1 of the 2 batteries die that the other will kick start and last longer?

[@electronash]

There is always a tiny amount of leakage current, even when the pin is set as an input. The pull-down resistor ensures that the leakage current goes to ground until the button is pressed. Obviously, a pull-up or pull-down resistor is generally required for a button because otherwise it would completely short-circuit when pressed. (you can't connect one pin directly to Ground, and the other directly to +5V for example!) tbh, a lot of stuff uses a pull-up resistor on buttons / switches though.

[@HarrisBallis]

1st of all great tutorials! 2nd I'd like to ask how we calculate the values of the capacitors at the voltage regulators example?

[@jons5794]

Hi there, just getting into electronics (engineering and computing) and I'm very interested with the theory behind the practical application. Two questions: 1: your picture during the voltage regulator section: Is that a 10K ohm resister? Does this mean there are 5/10,000 amps flowing through this circuit? 2: can I put a resistor anywhere in the circuit and have it carry the same effect... such as before or after the led?

[@rainbowsalads]

hi, in the photo diode example (10mins 30 secs) would it matter if the 10k and the photo diode were switched around?? or was the photo diode in the place of R2 (nearer ground)for a specific reason? : )

[@theowlsgo]

Would like to specify what blackhawk said earlier in that you need to specify your potPin as an analog pin with "A0" as opposed to just "0"

[@ivanreynoso3849]

Thanks, i learned a lot! (I'm typing this half way into the video) can't wait to see the last of it! but yeah thanks again, great video!

[@jayb198083]

Great tutorial, I really appreciate how you explain everything indepth and still keep it interesting, Thanks alot

[@multimirage]

Jeremy, thanks for your great video; How can we change outline shape of the board (to like circle or any arbitrary shape)?

[@1AppleMaker]

By 2 volt drop, do you mean that you have a 2 volt LED and that there is a remaining 3 volt to the resistor, because that is how I see it?

[@deafeyeskeys]

I have a question about when you are discussing voltage regulators. Will changing the size of the decoupling capacitors on either side change the output current? If so, how are the two related so I can determine the output voltage to be something other than 5v? Great videos, I saw that you wrote a book too, looking forward to reading it. -MEL

[@AlfredoAntonioMartinez]

Hi! just a question, how can I do to connect a LDR ( Light Dependent Resistor ) to the analog input, because I have tried like this example but I only have a 0 in the monitor, I don´t know if I need to add some resistor to the circuit or maybe need another componentes like transistors and like that, thanks a lot!

[@objectbeing]

love the videos. I'm still figuring this all out and your videos are amazing. Question. I'm running my arduino uno from a mac and the Serial command doesn't seem to do anything. I changed the command to Serial.print(digitalRead(buttonPin)); and that got it to compile however nothing happens when I upload the sketch. any ideas?

[@BjazzK]

Is the voltage drop across the led the same as the forward voltage? I have a datasheet for my led, but it doesn't seem to mention voltage drop. Thank you:)

[@TheGregGeek]

Man, this really made me want to go into engineering. I'm actually thinking of switching my major from CS to CE.

[@w0mblemania]

Re voltage dividers... I'd like to add an LED status light to my 240V AC powered hot glue gun. What would I have to do to make this work? Would I need a step down transformer, and rectification? Or is there is a simpler way? Thanks.

[@coxfox10]

I have that same robotic arm edge. Haven't messed with it since Nam'. Good stuff

[@electronash]

The 5V is not running to the pin when the button is pressed. What the pull-down resistor is doing is keeping the input pin on the Arduino from "floating" when the button is NOT pressed. A pin can be in a "floating" logic state, which means it's unstable, and prone to external interference etc. Also, with different types of chip tech, a floating input pin can float at a HIGH or LOW logic state, so confuse your firmware etc...

[@filiksawy]

thank you , i'm really appreciate your work that give me explanation for electricity principles that i was afraid of not understanding it for ever ,, thanks man

[@chengqi57]

a short question, do we need to connect external power supply for the 5V that is connected to the potentialmeter?