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.

Voltage Variator LM3900 (CB5057E)
In the figure we have a circuit that allows us to obtain a variable voltage of approximately 0.5 to 25 V...
1 W Amplifier with the TAA300 (CB6164E)
Found in a 1968 documentation, this small amplifier was very popular at the time being used in...
LM3914 20-LED Voltmeter (CB25457E)
This circuit has a scale of 0 to 2.56 V, but it can be changed by changing the values of the...