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Diode Clipper and LM386 questions

Yoa01

Jun 18, 2012
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Jun 18, 2012
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Hi all,

I have two questions for you today. The first is about a diode clipper. I am pretty sure this design would clip a signal, but testing it in LTSpice with a sine wave running at 9v yields a constant 7.6v. Is something wrong here?
clipper.gif

Secondly, I adapted the amplifier circuit from the LM386 datasheet and added a couple caps and a potentiometer for adjusting gain. I have seen in many 386 amp designs that those bypass or decoupling caps are used, yet the datasheet doesn't show them. Same with the caps leading into pin 3. Are they necessary?
LM386amp adj.gif

Thank you!
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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25,510
I have two questions for you today. The first is about a diode clipper. I am pretty sure this design would clip a signal, but testing it in LTSpice with a sine wave running at 9v yields a constant 7.6v. Is something wrong here?

Yes. It should clip.

Secondly, I adapted the amplifier circuit from the LM386 datasheet and added a couple caps and a potentiometer for adjusting gain. I have seen in many 386 amp designs that those bypass or decoupling caps are used, yet the datasheet doesn't show them. Same with the caps leading into pin 3. Are they necessary?

The best bet is to read the datasheet. They may be required under certain circumstances, or have to have certain values.

Or, they may not be required at all, and are performing a function external to the 386 amplifier.
 

Yoa01

Jun 18, 2012
214
Joined
Jun 18, 2012
Messages
214
I ran a real test, running a synth through it, and it did clip very well, though a bit quiet. Probably should have done that before posting, sorry...

Ok, I'll do that. Makes more sense anyway. Thanks!
 
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