Beacon with instrument (CB20495E)

This circuit causes an instrument needle to oscillate to signal an event. The circuit is powered by solar panel from 1 V.

Transistor Intercom (CB16408E)
This circuit was found in a 1980 publication. It uses only 3 easily obtainable transistors. It is a...
Multi Range Ammeter (CB10543E)
This circuit was published in an English magazine from 1977, but remains current, as we can...
Cable Tester (CB16567E)
The circuit shown is intended for cable testing, providing status indication via LEDs. The number of...