Found a documentation on PCs from 1996, this circuit can be used as a shield. The relay is rated at 100 mA of coil current.
This small amplifier with a low impedance microphone that can be used for hearing aid was found in a...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
This circuit is from a 1987 technical documentation. It consists of a battery charger and a system...