Solar telephone (CB20504E)

This low-power intercom can be powered by solar cells. The circuit is two-way, with an integrated of the time. The circuit is from 1991.

S meter (2) (CB1440E )
We find this circuit in a radio amateur publication of 1977. Its purpose is to measure the...
Small Amplifier for Microphone - LM386 (CB971E)
The fraction of watt amplifier shown can be powered by voltages from 6 to 9 V. It is not...
Dimmer (CB1592E)
Incandescent lamps, heaters and other resistive loads can be controlled by this circuit whose...