[mendiola]

Dear All:
 
Do you know how to detect amplifier oscillations with and oscilloscope ?
 
I have connected my oscilloscope to an 75 ohm metal file resistor and a 10K metal film ressitors.
 
The LM4880 output sine wave is Ok. (Input voltage 1.2 vrms)
 
If the amplifier oscillates does the sine wave get distort?
 
Regards.
Alfredo Mendiola Loyola
Lima, Peru

 

[jseaber]

This probably belongs in another category.
 
Anyway, a stable opamp should produce signal output with phase angle near 0 degrees (compare input to output). Oscillation also tends to produce harmonics, which are easiest to observe on an audio analyzer, or any oscilloscope with an FFT function. You'll see significant frequency content that should not be present.

 

[Mad Max]

If a chip opamp burns your finger when you touch it for a couple of seconds, it is definitely oscillating.