Comparator tutorial & clapper circuit
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- Опубликовано: 28 дек 2010
- A tutorial on op-amp comparators, and a demo circuit that lights up an LED when the sound volume reaches a preset threshold.
Watch this video on peak detectors next! • Peak detector circuit ...
More electronics at www.afrotechmods.com 
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I drove myself mad trying to figure out how comparators work. This made it super easy to understand thank you!!!!
Agree.
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
I know that making these videos may be time consuming and you probably have something better to do, but when I started to get back into electronics you were the best electronics channel on youtube!!! I image you still have a great deal that you can teach us, and want to thank you again for you help!!! 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
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!
Dude, this is hilarious and very helpful at the same time, thanks.
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.
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!
Your voice and all explain is really great
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.
I can use this in combination with a MOSFET/relay and a voltage divider to create a low/high voltage cutoff. very useful
You could also swap the v+ and v-, giving you a comparatator that turns off when the voltage reaches the threshold.
Once more, an awesome tutorial.
You just saved my semester!!!!!!
he just saved my job...
Afrotechmods - Thank you!
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.
@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.)
Hey! This channel is brilliant
@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 .
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!
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?
That was a great explanation!
Dude, your vids are epic! _/\_ Thanks a lot :)
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 ?)
maaaan you're God in explaining !!!!!!!
@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.
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
I love this guy! He's Awesome!
This is pure gold, thankyuo
Excelent, very good. Thank you
Great video ,just use this for my students
Hooker detectot, haha. You remind me of one of my favorite EEE professors, very knowledgeable, but not afraid to get us laughing.
this is a awesome tut. :D
@Afrotechmods If you used 8 comparators with different resistors (to change the volume threshold), could you make an 8 bit analog to digital circuit?
Man op amps are awesome.
Could you put a flip flop on the output of the op amp to have it to where you clap to toggle the led?
Hey Afrotechmods Could I use this in an audio circuit to detect any deviations from the audio input(distortion) and correct it?
I wouldn't recommend a simple comparator circuit to try correct distortion. It would likely be a more complicated op amp circuit with feedback.
great tutorial
GOOD WORK SIR
the possibilities are ENDLESS!!!
Good video! Thanks!
Excellent video thanks
@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.
I liked this video about .2s after "hooker detector". Also thx for the video, good stuff, learned a lot!
Well done sir
Very interesting. Thank you.
@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.
So is it a relay but with the switch pulled towards the side with the stronger voltage?
Explanation Thank you. It helped.
I dont mean a hooker detector... Brilliant!
awesome vid, much appreciated
Nice Video!
I like the burn traces on your alligator clamps.
Those are Used roach clips. Dude is cheap... And high~
awesome video thanks man :)
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?
How sensitive is this circuit? Does it turn on for other, loud sounds? Like two people rowing, or yelling?
What's soft do you use for your shema? (sorry for my verry bad english i am french ^^)
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?
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?
what would happen to the circuit if you didnt take off the dc offset with the high pass filter??
"and I don't mean a hooker detector" Perfect! ...and excellent comparator explanation.
what is the function of that 100k resistor connected from the output to the inverting input
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
Lol IC 555 is not an op amp
It is timer ic
Thanks it helped me alot
Thank you so much !
great video :D
I would like to ask if what will happened if V+ and V- were equal?
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)
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
good job
Haha, you think it's kids-friendly education until you're hit with the hooker detector line :D
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?
That would be Electronics Engineering. Get hooked! Watch his other videos, also AddOhms, EEVBlog, GreatScott, ElectroBOOM just to name a few.
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
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
It's voltage divider
Did you use only one 5V power supply in that 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
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 ?
Don't use the LM741 it is an awful, outdated part with a lot of quirks and nonidealities
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.
thanks a ton broooo
can u tell me the part list to make this circuit?
This is hilarious haha 😆 keep it up!
Thanks very much
qubin black markeket is where i got mine!! ;)
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.
Hello, If I have a question?, can you help me?, how I can contact you?, thanks
Electronics are fast and fun with you!.
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)
can you make a circuit board for testing LM324N ?
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?
Does it matter how many volts go into the op amp? Will 24 kill it?
why do we need to remove the offset?? and how the offset can be removed with high pass filter?
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.
Hey afro how can i hook this up to a arduino
OMG you're right... Must have been because of that Cuban black market op.amp
I have a quad 339, under the first test it doesnt work? :/ Could I have a little help please.
thank you soooooooo much bro
Afrotechmods Imperial!
Man I can make those memes with these