Ok, the schem says drive with 1kc signal at 10Mv.

I do that and the output is just about like the input.

A pretty good sinewave.At 20mv`s it starts to clip at the top,BUT it still has a lot,lot more output than whats at the input.

I can`t use another amp just like this one cuz now we know it clips at 20mv,and the output of this one is a lot more than 20mv.

How a bout a linear amplifier on the output?

I built one about a week ago but it didn`t seem to work to good.

Output was way below input.

 

I don't understand; are you saying that you think the amplifier is clipping too early or asymmetrically?

Have you checked the DC operating points of Q1?

 

This is strange~

I had it on A populated breadboard and the DC biases were right on the money,according to the schematic.
so I transferred it to another unpopulated breadboard,same exact kind,and the voltages dropped to about 4 volts on E,and 4.61 volts at B.

So the bias dropped about .9 V,BUT it still amplifies very good.
I still get the same scope pattern I got before.

 

I don`t think it clips to early as the input was stated as 10 Ma.

It shows a pretty good pattern at that amount but turn it up to 20 ma and it looks like its turning into a square wave instead of a sine wave.

Square waves are supposed to be a bunch of sine waves together.

I`ve never heard of getting Square from Sine by overdriving an amplifier.

 

Square waves are supposed to be a bunch of sine waves together.

I`ve never heard of getting Square from Sine by overdriving an amplifier.

Then you have mis-understood square waves. Connecting a sine wave to a high gain amplifier or comparator or a logic gate is exactly how a square wave is generated.

 

Then you have mis-understood square waves. Connecting a sine wave to a high gain amplifier or comparator or a logic gate is exactly how a square wave is generated.

Ah,so anytime I make or use an amplifier and a sine wave comes out Square,its being overdriven.

Good to know.

 

Ah,so anytime I make or use an amplifier and a sine wave comes out Square,its being overdriven.

Good to know.

And if it is clipping, it is either
- a) too much gain
- b) DC bias is not centered (if clipping only on half cycle).
- c) trying to drive too big of a load (e.g. speaker resistance is too low).
If c) it could be because...
- output impedence is too high
- power supply is dropping out from too high of a load.
- power supply filter capacitors are not big enough.