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By RoboMan
This is my first pcb and as i expected it does not work.I am using a lm324 to make a small amplifier for my ipod.When at first it didn't work i check my voltage and discovered that my battery was dead so i got a new battery (9v) and when i plugged it in my 1n4001 diode got extremely hot really fast i checked for a short but i do not see anything could i be trying to draw to much current from the diode.
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By leon_heller
The LM324 is an op amp, and isn't suitable for that application.
By esklar81

This forum community is full of members who are knowledgeable, intelligent, and helpful. AFAIK, though, none of us is psychic. :( If you'd like someone to help you figure out what happened, you'll need to provide, at least, a schematic of your circuit.

By RoboMan
Sorry here are the schematic and board files.
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By leon_heller
As I said, forget about using an LM324.
By esklar81
Whether or not an op-amp is suitable for use in an audio amplifier is not central to the original issue, which is why did the diode appear to overheat.

Here are some questions and suggestions to help you in analyzing what occurred:
  1. What information about the LM324 did you use in designing this circuit? It appears you have confused the inputs marked "+" and "-" with inputs for the positive and negative poles of an audio signal. I suggest you start with a basic tutorial on op-amps (GIYF) before you make another attempt to use them.
  2. Yes, you could be drawing too much current through the diode, but that seems unlikely. The diode appears rated for 1 A and it seems unlikely your circuit got there without a short. One question which occurs to me is how hot did it get? That is, did it get hotter than it is predicted by its specifications to get under the use conditions?
  3. What, if anything, did you have connected to the input and output terminals when you powered the circuit? If they were connected, what signals or bias voltages were being supplied? What were the impedances of the loads?
  4. Did your power indicator LED survive the test? If not, is it now a shorted? A typical indicator LED has about a 2 V forward voltage (Vf) and will tolerate about 20 mA. If you provided 9 V to the Vcc terminal, I'd expect about a 1.1 V drop across the 1N4001, putting Vcc at 7.9 V. If the LED's Vf is 2 V, that leaves 5.9 V across a 100 ohm resistor. I = V/R = 5.9 V/100 ohms = 5,900 mV/100 ohms = 59 mA.
  5. What are the voltage and capacitance ratings of the three capacitors?
  6. Was your intention to keep the signal grounds isolated from the power circuit ground? If so, does the op-amp's datasheet support that?
  7. The datasheet I found for the LM324 shows the DIP as 14-pin; you have drawn it as 16-pin. Which is correct? If you have a 14-pin part and a 16-pin board, what pin of the device was connected to what else in the circuit?

Happy Hunting,
By RoboMan
Thank you for all your help esklar81.

The diode became to hot to touch for even a second almost instantly.I tested the led and it still works when i plug the amp in the led never lights up.The capacitors are rated for 50 volts and have a capacitance of 1.0uf. I think i am going scrap it and try designing one with two lm386's and bigger caps and this time ill do a little more research lol :oops:.
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By leon_heller
The TDA7052 is much better than the LM386.
By teprojects1

LM324 is a four channel operational amplifier, which is also abreviated as op-amp. As I said four channel, that means it has four amplifiers embedded in a single chip. You should download its datasheet to read more about it. You should also download this Proteus Simulation of LM324 it will help you if you are planning to start working on this IC.

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By darrellg
You should really start looking at the date on the threads you reply to. This one is over 7 years old.
By teprojects1
Yeah but its an active forum and you must check the link. It will help the readers positively.