Comparator tutorial & clapper circuit 

I drove myself mad trying to figure out how comparators work. This made it super easy to understand thank you!!!!

thanks again Afro Man, I used this comparator circuit to make my own solar charge controller, and a boost converter to set a reference voltage, with a 555 to time a relay to allow the comparator to sense the battery voltage. its very simple and I can fix it if anything goes wrong. I personally want to thank you and so many others that have contributed to my knowledge base, when I need to design something, I just go back and refamiliarize myself on what I was taught by all of you, thanks mike

just wanted to let you know I use this circuit quite frequently, and use this video as a reference, thanks AFTROMAN, I wish you would start making videos again. you are and will always be the best in my book!!! mike

Dude, this is hilarious and very helpful at the same time, thanks.

spent a large part of yesterday searching for a clear example of the output voltage because everywhere I read it sounded like one of the comparators would become the output and it didn't make sense... this video was perfect for me, thank you!

Thanks for the informative video! Was able to apply this in comparator circuit for a thermistor controlled fan in my DIY power supply. Much more sensitive than using a single BJT and easier to adjust. Great voice, by the way.

You could also swap the v+ and v-, giving you a comparatator that turns off when the voltage reaches the threshold.

These are good videos, so clear to understand.

Many thanks. I was having trouble understanding opamps and as soon as I saw this i fully understood it's purpose. Especially as i am using one with a transistor to control a USB VCC to power rail when 12v VIN is not present. Thanks!

Holy cow...I just tried this circuit and it worked! I'm thinking of using this circuit with two thermistors on the two inputs as part of an automatic temperature compensating thermistor-based low fuel warning system on a motorcycle. The factory ones are thermistor based, but very crude. They only use one thermistor and are subject to temperature extremes that render them inoperable...

This one was especially helpful to me, it gave me new insight into some of the circuits i am designing right now.

Your voice and all explain is really great

I can use this in combination with a MOSFET/relay and a voltage divider to create a low/high voltage cutoff. very useful

@TheJagwtf Think of the ground as just a point where all the "grounds" are connected. Usually the ground is connected to the battery (-) terminal, but *not* always, so don't rely on it unless it isn't specified. Wherever you see a ground symbol, mentally draw a line to the nearest ground. It's convenient because otherwise schematics would just get cluttered with links between all the grounds. It's a similar story for voltage symbols (like 3.3V, 5V etc.)

Awesomely put, I finally understand how op amps work❤

You just saved my semester!!!!!!

Many thanks for this great example, I have tried it and it works correctly on a breadboard but not on a strip board. What sort of decoupling/bypass would I need and where? Also I have also been told to ground the any unused inputs to ground, would this be correct?

@sinupinginaaber Try turning down the power supply to 4 volts or so. I built the peak detector version and at 5 volts it stayed on. At 4 volts it worked right.

Could you put a flip flop on the output of the op amp to have it to where you clap to toggle the led?

Hi. Your tutorials are excellent. I'd like to ask you: How should I use Op Amp when I want to check lower and higher voltage limits (when the output signal of the peak detector is in wide range 0 and +5 volts, but Op Amp should be act only when the signal is between +3.0 and +3.5 volts)? Should I use two Op Amps or Should I use voltage devider to cut off lower voltage right after output of the peak detector? Thanks.

Once more, an awesome tutorial.

I would like to ask if what will happened if V+ and V- were equal?

Thanks! Can I adjust this circuit low enough to be sensitive to voice (think VOX control) or do I need more amplification/ components? Thanks for the video!

Hey! This channel is brilliant

@Afrotechmods I used the same circuit with a TL082 op amp. I am using a 100KHz sine wave input 1Vpp and want the circuit to trigger when the signal is at about 90% amplitude. However, The circuit's output is not stable. Using my scope, i can see the output is very stable for sometime (1-1.5 mins) and then the amplitude of the output reduces for about a minute and it again stabilises for a minute. rinse and repeat. how do i stabilise the output?? (P.S. the input is perfect, no problems there). I could email the screenshots to you if you want to have a closer look.

Why do you have a pull up resistor (1K) before the cap and a pull down resistor (100K) after? Is it to make sure that we always have a reference voltage of approx 5V?

hey, amazing videos, love the way they are made, could you please explain, i suck at reading diagrams i don't really understand where do all you ground go ? I know what ground is earth - wow captain here ground wire, or N wire - 0v or its anything that's grounded taking into account this circuit where do all the grounds go, please give some examples, (taking that im using a retro-fitted Pc PSU will the 0v wire be my ground ?)

@afrotechmods Hello , I find your videos really helpful. Can you please tell me whether , I can take the output of your clapper circuit , to a 4th order butterworth low pass filter (1hz - 1.5khz) to limit the different frequencies , generated by different sounds , just so that the output of the final circuit with the filter only responds to certain freq's which can be then sent to a pic micro controller .

what would happen to the circuit if you didnt take off the dc offset with the high pass filter??

Dude, your vids are epic! _/\_ Thanks a lot :)

Hooker detectot, haha. You remind me of one of my favorite EEE professors, very knowledgeable, but not afraid to get us laughing.

Afrotechmods - Thank you!

I'm thinking about using this circuit in a clap activated outlet plug, so all I have to do is clap and anything plugged into of turns on or off

Can you make a tutorial explaining how a Schmitt trigger works. Thanks in advance.

I'm using two LM741, but for some reason, my LED is always on. I debugged the circuit I found out that I have a high voltage at the first output (3.9V), I apply 5V at inverting of second op-amp, but I still have a problem.

Hey, nice tutorial. What would be if we connected the LED through resistor to the output of the first op amp. Why do we need the right part for the LED instead? Thanks

So is it a relay but with the switch pulled towards the side with the stronger voltage?

what is the function of that 100k resistor connected from the output to the inverting input

why do we need to remove the offset?? and how the offset can be removed with high pass filter?

Why my Output needs to be connected to the +5V in order to make the LED light up (with the current limiting resistor of course)? I'm using a LN393.

Hey Afrotechmods Could I use this in an audio circuit to detect any deviations from the audio input(distortion) and correct it?

@Afrotechmods If you used 8 comparators with different resistors (to change the volume threshold), could you make an 8 bit analog to digital circuit?

i had to sign in to my google account to subscribe and like the video..i think you know how much i liked it :D

That was a great explanation!

@CassetteMaster i discovered my problem was actually the tripping voltage. i didn't pay attention to the resistor color scheme, so i used a 100ohm resistor instead of the 10k resistor, and i quess i had too much noise in my room, so the LED couldn't turn off. i changed the resistor and now it works. but thanks anyways.

How sensitive is this circuit? Does it turn on for other, loud sounds? Like two people rowing, or yelling?

Could you explain more how you would use a transistor to switch motors on and off. Using MOSFET I assume? I would need to cut off the Hbridge power which is driving my stepper?

How do you do the actual pin out on 555? I am banging my head against the wall missing something .... 5 pins are used- I get that/ but I can’t get it to work

I like the burn traces on your alligator clamps.

can u tell me the part list to make this circuit?

damn i have bad luck i have a lm339 quad comparator from radioshack, i hooked it to 5v and GND and output to a led when i power it up and set the + to 5v and - to GND nothing happens when i switch it samething nothing happens i tried it with 3 different ones =( any help would be appreciated

Great video ,just use this for my students

I love this guy! He's Awesome!

maaaan you're God in explaining !!!!!!!

Does it matter how many volts go into the op amp? Will 24 kill it?

I dont mean a hooker detector... Brilliant!

Can you make a video tutorial on a transistor comparator?

Look at the schematic at 1:53. The pot is labeled their (It's the sign that has an arrow pointing at the middle of a resistor symbol)

i notice your bread board setup.. care to explain?

Excelent, very good. Thank you

how many volts and amps can this op amp handle? would i be able to hook up a car battery to this chip if i use resistors?

when you say i could compare audio signals how would that be wired? im trying to have the gate be opened whenever an audio signal is present, with the reference voltage being 0v so that way any voltage on the other side opens the gate, and the voltage comes from an audio signal. HELP!!!

the possibilities are ENDLESS!!!

Man op amps are awesome.

I’m using a LM741 op amp in my circuit and using this comparator configuration. Power by 9v and ground. I’m feeding 3v into the inverting and 5v from a 4081 quad AND gate IC to the non inverting input , but for some reason I get 1.2v output when the inverting is at 3v and the non inverting is at 0v. Why would this be ?

What if V+ V- Is equal?

my LED just stays on. i have checked the circuit 6 times and made sure everything was exactly like in the schematic. I need a solution, please.

how to solve the output voltage if Vref > Vin?

could I use this for a Li ion battery protection?

Very interesting. Thank you.

Great vid, but HOW does a comparator work. Not what does a comparator do. I am so curious but Incant find it anywhere

great tutorial

Did you use only one 5V power supply in that circuit?

this is a awesome tut. :D

I'm using LM324N. I build exactly the same as your circuit, but the problem is LED always turns on. When i speak in the mic, LED flashes, but why LED is always ON? can u help me please?

3:09 Hey, may I ask something? Why there is 100k resistor added? If I'm correct, thats voltage divider, but why? Most of voltage goes to transistors gate anyway, because of the resistors values.

GOOD WORK SIR

"and I don't mean a hooker detector" Perfect! ...and excellent comparator explanation.

What's soft do you use for your shema? (sorry for my verry bad english i am french ^^)

I have a quad 339, under the first test it doesnt work? :/ Could I have a little help please.

did anyone notice the nuclear detonator 3:00?

I liked this video about .2s after "hooker detector". Also thx for the video, good stuff, learned a lot!

What is V- = V+ ?

OMG you're right... Must have been because of that Cuban black market op.amp

Explanation Thank you. It helped.

Hey afro how can i hook this up to a arduino

Excellent video thanks

but..! what happens if V- and V+ on the op-amp is EXACTLY the same??

This is pure gold, thankyuo

Does it matter if we connected the LED before or after the resistor?

could you please explain to me why my light comes on when my finger moves over the capacitor filtering the mic dc. I am scratching my head as to why this is happening. Also more videos please they are great. Nicely explained and easily understood you should become a teacher in this subject.(unless you allready are)

3:40 is that circuit same for all Microphones?

can you make a circuit board for testing LM324N ?

i have a question : whererfore is the 100K Resistor at the scematics in 3:00 thanks in advance :-D

Well done sir

you didn't tell as what happens if we feed the inputs the exact same voltage. Will output be high or low?

what's the difference between a comparator and a op-amp ?

hello afromods, i can't do the comparator, i followed the schematics, i'm using a 741 with a 9v battery, i've played with resistors but still can't get any output voltage, what am i doing wrong?

hey i like this and actually watching this because i wanted to know about real comparators while i learn about them in minecraft lmao, anyway if i wanted to learn more about this kinda stuff u showed in video what field would that be called exactly like if i wanted to look up videos and or go to classes for it?

1:51 why is there a resistor before the ground? i think this is too advanced for me, what source would you recommend for learning how to make circuits, specially for audio? this channel is great, but it goes over my head