Low battery indicator 555 (CB9551E)

This circuit can operate with different voltages, depending on the zener used. We found it in a 90s American documentation.

AC Motor Speed Control (CB16747E)
This 1992 circuit has a diode normally replacing the diac that is used in this type of...
Adjustable Field Strength| Meter (CB5188E)
The circuit presented may use any general purpose transistor. The indicator is an LED and...
Regulator 0 to 50 V (CB8899E)
Found in a 90s Radio Electronics, this circuit can supply currents of a few amps, according to the power...