AC voltage probe (CB8185E)

This circuit for voltages up to about 20 V was found in a 90s Popular Electronics. The LED can be of any type or color.

Discrete Precision Regulator (CB15719E)
The voltage regulator circuit described is highly accurate and uses discrete components...
WWV 10 MHz converter (CB9184E)
WWV is the standard frequency station of the United States government. This station broadcasts a...
Voltage Detector for Battery Chargers (CB6061E)
Based on a 555, this 80's American documentation circuit detects the voltage of a battery and can then...