LM386 opamp Module, measuring amplified output without giving it input

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Arjuna_1000

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Hi. I am using an LM386 opamp Module from Amazon. I am powering it with a 5V input (just to power it, not intending to amplify anything at this point). Nevertheless a multimeter measures an amplified output of around 1v-2v.

When I put an actual input that I want to amplify nothing really changes. Why I am getting an output without giving input?
 

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Possibly due to the small leakage current through the output coupling capacitor.
This is nothing to worry about.

JimB
 
If the input terminals aren't connected to an intended signal source then they will pick up stray signals from the environment. Mains interference is a common culprit.
 
Arjuna_1000 said:
Hi. I am using an LM386 opamp Module from Amazon. I am powering it with a 5V input (just to power it, not intending to amplify anything at this point). Nevertheless a multimeter measures an amplified output of around 1v-2v.
Click to expand...

Well first off, it's NOT an opamp module, it's a small power amplifier module - if you want an opamp, then use an opamp.

Secondly, don't stick a multimeter on the output - it's completely meaningless, and won't give any useful indication at all.

Stick a small loudspeaker on it (as it's intended for) and see what you can hear.
 


Thanks. I connected a speaker to it as you suggested and it worked. Then I was actually able to measure the voltage change as I intended in the first place.
 
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