Microammeter (T465E)

Found in a 1948 MIT documentation, this circuit uses a 0 to 100 uA microammeter as an indicator. The power supply is 150 V.

Courtesy Light Expander (CB4958E)
This circuit keeps the courtesy lights of a car on for a while after the doors are closed. The...
Continuity tester (CB9326E)
This circuit was obtained in an Electronics Now from the 90s. The circuit uses operational...
VHF Amplifier (CB3886E)
This circuit was originally designed to measure the gain of two-door RF MOSFETs as indicated by...