Trustfire Multifunctional Lithium Charger whines when connected to power.

[ledmitter]

This one. It's a high pitched whine that seems to fluctuate
both while charging and with the batteries out.

It's loud enough to be audible but not necessarily annoying.

Anyone else? or is it a ticking time bomb?

 

[moderator007]

Mine makes a slight hum while in use. Kind of sounds like a power line transformer but not as loud.

 

[CKOD]

Switchmode power supplies can hum for various reasons, (noise while running normally, frequency varying under load, pulse skipping under light loads etc...) I bet others would do it too if you listened in a quiet place.