I'm having trouble to understand why this is happening when I power my LM386 on a 9V battery with no load.
The schematic is the basic application from the LM386 datasheet with the gain of 20 but without the speaker load at the output.
When I measure the AC voltage at Vs I get a really high frequency signal (10MHZ) of small amplitude (10mv).
Now the thing is that this noise get amplified at the output too. This wouldn't matter much if I was using a speaker as a load (because I shouldnt be able to hear that frequency I guess) but I want to use a vumeter as a Load.
I tried the following:
1. Adding a 220uf cap at the power trail, this helped a bit and reduced the amplitude by 50%, but I'm not sure if that's the right approach and I would like to remove completely this noise.
2. Adding the zobell network, this didn't do anything.
3. Adding a fake load (a 10K resistance) at the output, didn't do anything.
4. Also grounding all the floating wires to ground didn't help
Why is this happening and how can I remove this signal ?