Peak detector circuit tutorial for beginners

Veri explanatory thanks🎉

Nice info, thanks for sharing it:)

Afrotechmods, return to us

Excellent friend, you earned a new subscriber from Venezuela. Thanks for sharing.

very nice video well explained, got a question can I use this same circuit as an audio peak led, working with my vu meter, I would remove the mic of course and that would be my audio input, what sort of adjustments would I have to make to the present circuit, and I would like the circuit to have a variable resistor to control the led, and what op amp are being used. Thank you
donald

awesome!

👍

You are a gem. Keep it up! 👍

Could you please explain why you did not connect the resistor in series with the capacitor instead?

wait but i have a few issues here. if you have a bigger capacitor doesnt it take longer to reach the peak that it is detecting, and the bigger the resistor I would think would dissipate the voltage faster or have some other negative tradeoff effect.....hopefully you get what i am trying to say....I imagine there is some balancing act and other considerations not mentioned here....

Please advise.

Thanks Afrotechmod, this is short, concise and really helpful little circuit 😉 .

this cricuit gives me an idea for something fun!

Could this be made into a sort of amplitude comparator for a direction finder

Thanks, sir, hope you are happy and healthy!

I find your videos very straight forward and easy to understand!

This a circuit which is used to charge battery in cheap China made emergency lights

This an absolutely outstanding channel! ⭐️⭐️⭐️⭐️

These are real engineering classes. Our university was completely ignoring the labs that I’m still trying to teach myself 12 years after graduation. It means the theory teaching were in vain as well.

10 years ago, are you kidding me.

What if you make it that you clap once and it charges the cap, then if you clap again it discharges it immediately

2 questions:

While elegant in its simplicity, this implementation of the peak detector seems to have a pretty serious flaw. Judging from how long the led stays on at different occasions (i.e. how much the capacitor has charged) even if the first clap is loudest, the consecutive claps seem to still charge the capacitor. If we think about a more useful implementation where some sort of meter would indicate the level of the loudest clap, it would fail by adding a bit to the reading by every clap even if they were preceded with a louder one.

..As I wrote that I did come to think that this might be only a problem due to the charging time of the capacitor (which of course isn't instant even without notable resistance).. So, if we'd imagine the cap could charge instantaneously while maintaining its discharge properties, would it fix the problem?

I mean, as the capacitor charges, the voltage at the capacitor's 'upper' plate rises and so there would not be potential difference over the diode unless the clap would be louder than its predecessors?

Another thing... wouldn't the level of the peak affect also the hold time? I'm not saying this is necessarily a bad feature, it might even be a preferred one but just want to know if what I've understood so far is correct.

GOOD Thanks!

yes , i enjoyed seeing your video as it is close to something i'm working on.
and am tempted to use your MIC amplifier idea instead of the max4466
and 9814 modules bought on ebay. except the 9814 has AGC which
is a problem solver in itself. for my projec tthe comparator step you do w/ an op amp
is handled in code with an if-then statement

overall it includes taking sounds that are brief and intermittent and capture them
with your circuit plus a Picaxe uC with ADC pins. a 20M2 at this time

lots of new ground to tread . with many interesting challenges along the way .
practically everything is an unknown when doing a big project like this for
the first time. here are some of the problems that have arisen along the way :

a) figuring the gain for stage 1 based on the volume
of the incoming sound

2) determining the R-C values so the cap' voltage fades enough
to be taken as a new sound when the ADC is looping-repeating every 250mS or so

3) test the ADC level output of each sound w/ the uC to be above some threshold in a 0-255 space
and keep track of how many sounds over one second meet a volume spec'. etc.
this is the comparator step mentioned above ... done in code.

4) re-learning the exponential equation for cap's : V=Vc * e ^ t/RC

5) lastly is managing the voltage levels with the FVR2048 voltage reference
directive so the ADC uses its converting voltage space most effectively

a few things yet to learn :
a. how to deal w/ the 9814 and its mid-range DC offset ... what does the ADC do with it ?
b. to store the count of noises in inner 1-dimensional arrays or ext'l EEprom ... ??

another matter is not knowing precisely when the uC samples the ADC pin.
the PIC uC's dont give you access to the inner register bit change when 'GO'
happens. so right now the best i can do is code a 100uS pulse before and
after the readadc command. then , on the scope, the 2 pulses serve to frame
when the adc pin does its sampling. this allows seeing how well the ADC
aligns with the peak detector when the DC voltage is flat

such a simple looking circuit leads to many new directions. and stops your
progress every time you run up against the end of your knowledge.

then you might find yourself searching u-t for others who too have tread this path

i'll be looking thru your other videos to see if you are including uC's ...

We miss you man, I hope you are well.

Werent similar circuits used in Attack/release filters in old analog synths?

And if you choose your C and R carefully you get a simple envelope detector. For demodulating
some AM signals

Good one and many thanks. Very short and apt video. Your subscriber base just increased by one.

U Are Great......!🙏🙏

+Afrotechmethods
Couldn't you improve the sensitivity of the peak detector by using a germanium diode? I mean, Ge diodes have a forward voltage of around 0.2volts, compared to the typical 0.65 volts of a silicon P-N junction.

This counts as studying for my EE final right?

Thank you

It does explain clearly what would take hours in books such as op amps for everyone

The capacitor doesn't have a path to discharge? Wouldn't that be ground?

The peak voltage has to be around 5V to light an LED with this circuit. I tried it with the input signal biased to the middle of the 0 - 5V range (the typical workaround for using CMOS switches with a single voltage supply), and nothing happened.

you are an amazing dude

I don't understand why the discharge / charge formula is 5*R*C and not just R*C

perfect tutorial video I have watched so far

Can you move the diode+R+C circuit after the amplifier (before the led basically)? Is there a reason why you put it there?

Holy shit, this is how a compressor works. The detected peak is used to pulldown the audio signal.

dnt know its edited or not but i just love ur voice..

glad I found your channel

Thank you

i know that the discharge time is about the time constant.
But how about the charging time?? why shouldnt the charging time also equal to discharge time?
please anyone

Could you show how to wire up a logic flip flop to the comparator's output so it becomes a clap on-clap off switch?

outstanding man

You Sir are amazing! You explained this topic in an interesting, fun, but still usefull way. Thank you for makeing so great and understandable videos!

Yes!!

was this schematic built using spiceLT ? also can we use this sim prog to make our own passive components ? sorta like prototyping a new type of component ?