3-Stage Level Indicator (CB24561E)

Using the Texas Instruments SN75489P this circuit was found in June 1978 Radio Electronics magazine. The power supply is from 10 to 18 V.

Secret Combination (CB9879E)
This game aims to make you discover which is the combination of activated switches that make the...
1 A Adjustable Power Supply LM109 (CB14501E)
The LM109, which is not common today, was manufactured by many semiconductor companies. This...
400,000 ohms per volt meter (CB23711E)
This adapter circuit for measuring voltages was found in Radio Electronics from April 1966. The...