LM386 opamp Module, measuring amplified output without giving it input

[Arjuna_1000]

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?

 

[JimB]

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

JimB

 

[alec_t]

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.

 

[Nigel Goodwin]

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.

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.

 

[Arjuna_1000]

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.