Astable 555 (CB21101E)

This 50% duty cycle configuration was found in a Popular Electronics from the 1990s. The operating frequency is given by C1.

High Voltage Inverter (CB25669E)
For experiments with ionization chambers and Geiger valves this circuit generates high voltage from...
Simple DC Motor Control (2) (CB11600E)
This control allows to start or stop a motor up to 3 or 4 A with a low intensity signal. The...
Solar beacon (CB20489E)
The battery is charged by the photocell that keeps the low consumption beacon in the dark. The...