Seeing this circuit is one thing, but having the reason for peripheral components explained in a very clear manner is a total other ballgame. Thank you so much... wish I would have gotten into this when I was younger, but no time for regrets!
I understood SO MUCH with your video than in any video I have watched. I'm serious! Thanks for your explanation of this circuit! You are really great teacher.
As an Advanced avionics tech at Boeing for 30 years I saw a lot of engineers with book knowledge and no practical experience with real life application. It was our job to lead the engineers as what a circuit really did in real life circumstances compared to paper
Thank you. I learned more in 12 minutes than I have in the hour I spent poking around the web. The only thing I missed was why you added the 10uF cap between the audio source and pin 3. I assume it is used to prevent clipping or filter out AC voltage. Again, many thanks from an old guy trying to learn new tricks!
+Rick Schrager I'm glad the video was helpful. The cap is there to block any potential DC voltage from flowing into the input of the amp. It only allows AC voltage (the audio) to pass.
Hooked up a 555 timer with a flashing output installed the lm386 and got an ok sound but want it louder put in the cap on pin 8 and 1 but no difference even with the cap on pin 7. Any ideas ?
Hi i want to make this circuit for my little radio, to make it louder but i also want the bass function. what do i add or change in the circuit ot activate bass.
Excellent explanation! Not that I understood everything, but I find this very interesting. Is there a book or resource you would recommend for learning circuits. I’d really like to build a pedal. I’m thinking fuzz is probably one of the easier ones to do. Where would I start?
I really enjoy your video’s, the explanation and practical uses of the circuitry. Sometimes I have a hard time following because I was thought electron current flow but you explain things from a conventional current flow, also known as (Hole Flow). I know either works but it’s still rather difficult seeing it explained in a different direction. Maybe you can share something that could help me?
Hey, great video. I took this information and built an amplifier using the LM386. As a source, I used my Siglent SDG805 function generator and was making all kinds of tones. lol. Driving the wife and kids crazy. Thanks for a great video. You should do more!
Thanks! I'm glad the video helped. When I'm teaching I like to use a function generator to test a room full of people to see who can hear the highest frequencies. I had one guy drop out after 8kHz. I wondered why he always seemed to be shouting. Anyway, glad the video was a help and there will definitely be more in the future.
I used the same circuit to build a audio amp and it produced a considerable noise ,to decrease it could I remove the potentiometer and just keep a 10k resistor ? And another question in case if we use the capacitor between the pin 1and 8 to inc the gain is it necessary to use the bypass capacitor at pin 7 ? why the decoupling capacitor is polar ?
+Amarnath Karthi Question #1: If you get rid of the potentiometer, how do you propose to use the 10k resistor? Will you connect it in series with the capacitor or bring the resistor to ground? Each will have a different effect. Neither will do a decent job of decrease the input levels like the potentiometer will. Question #2: It's not necessary to use the bypass capacitor, but when you start to hit higher gains by putting a capacitor between 1 and 8, you might need it. It helps to keep noise out of the earlier amplifier stages. It might help with your noise issue. Question #3: The decoupling capacitor is electrolytic. It's electrolytic because at a higher capacitor values, electrolytic capacitors are cheaper and reasonably sized. Because it's electrolytic, it will be polarity sensitive or polar. It doesn't have to be electrolytic. You could use something else however it might be larger than you want and cost more than you might want to pay.
in almost all the other opamp vids I watched, they all use closed loop configuration. But in audio amps, they all seem to use lm386, and it's often open loop. Is there a difference between lm386 and your usual opamps?
I've seen lm386 circuits with seperate grounds for power and signal and also with caps on the input stage as well just wondered if you knew of this and could explain the theory behind this practice. 🤔regards Kevin
10µF is a good value because it helps to short out those audio frequencies being produced by the amp. It doesn't need to be electrolytic but it's probably cheaper.
i enjoyed ur videos, plz do more vids of explaining weird schematics, also im getting the sound i want along with fuzzy noise, do u know hw do i get rid of that,
+aravind jayanthi Yes. The capacitor blocks any DC voltage that might be present on the output of an audio source. For instance, I use a lot of powered microphones. The capacitor blocks the DC voltage used to activate the microphone but allows the AC signal produced by the microphone to pass to the amplifier.
When I take out the potentiometer because I control the Volume with pins 1 and 8 by putting a potentiometer between them and the capacitor only using 2 pins of the potentiometer , can I just let out the potentiometer on pin 3 or do I need to add 1 or 2 resistors?
+Nick Sebring No, you would not need the 10k resistor. The potentiometer in the circuit is just there to vary the input level of the audio. If you don't need that functionality, leave it out. I would keep the capacitor between the audio input and pin 3. Have a great day!
1.is there any reason for using polar capacitor for decoupling and also between potentiometer and pin 3? 2.in my project which involves the use this lm386 circuit we used with input as mobile phone and out with a speaker , in order to reduce the noise can we remove the potentiometer as we can control the signal power with the volume rocker ?
+Tatsuya Shiba 1. The only reason I'm using that capacitor is because it's easier to find electrolytic capacitors at that capacitance. Many times they are also cheaper and smaller than their ceramic counterparts.2. You can remove the potentiometer but I don't know if doing so will solve your noise issue. I would think keeping it can only help.
hey, great explaination! Thank You! Ive got a question about the formular, what is R ? (R1+R2 ?) in wiki there is it but instead of R there stands R2 (again) for . please explain it... I´m not that in... so maybe it is a stupid question... in case, sorry for that ! ;-)
Thank you very much sir. Sir i want to know about the highest value of capacitor that we can use to increase gain between pin 1 n 8. Is it necessary to add a resistor in series with the capacitor? please specify values also.
+shubham kushwaha The datasheet recommends using a capacitor of 10µF. This will increase the amplifier gain to 200. Without the capacitor, the gain is 20. It is not necessary to add a resistor in series with this capacitor. If you do, you will decrease the gain.
I use this circuit with 12 volts but after 3-2 trials the chip burnt. I tried with 2 chips and both have same problem so what is issue with 12 volts. I am using 3*18650 cell as power
Thanks, nice informative vid on a basic amp circuit bit of a refresher from school anyway, found you on G+ too btw, seems to be easier to find more interesting things than cat videos
The 12V source should be fine, but I would make sure not other AC noise is coming across the 12V transformer. If that transformer is connected to mains power, you might end up fighting a pretty nasty 60Hz hum noise on the output.
For most LM386 chips, 12V is the high end of the voltage range. There are some chips that will accept more. As far as current, it shouldn't matter that much. Also, if you setup the circuit right, the speaker shouldn't be affected by the voltage because it is protected by a fairly large capacitor.
+Skinny R&D Let me put it another way. Can the sound from a 555 timer be increased . Currently I have pin 3 going to a resister then a transistor . I have the speaker hooked up to the transistor collector and ground . I would like to make it louder I was hoping an amp would do the trick but no luck with the lm386 hope this helps I will draw up a schematic and figure out where to put it if you still need one . Ps the sound is going off and on like a flashing led which is what I want so that part is good. Just not loud enough for what I want it for Regards
+RC Canuck Yes, the sound from the 555 Timer can be increased by using an amp, but it can only increase to the voltage level you are supplying. According to the datasheet if you use a 5V source, you will get an output high of 3.3V. Even if you put that through an lm386 with a 5V source, the highest output on the amplifier you can hope to get is just under 5V no matter the gain setting. You may need to power the amplifier with a higher voltage source and then put the speaker in the configuration shown in the upper left hand corner of page 5 of this this pdf: www.ti.com/lit/ds/symlink/lm386.pdf With all that said, I've not hooked a speaker up to the output of the 555 timer. I've only used ultrasonic speakers. Those work pretty well. Is the speaker you are using an 8Ω speaker. Let me know and I may try it for myself when I get a chance.
