This circuit protects galvanometers that are excited by low impedance amplifiers. The circuit is from na old Electronic Design. The components are from the era.
If the input voltage falls below 12 V the LED glows up. Other voltages can be monitored by...
Found in an old Popular Electronics, this circuit warns when a remote lighting system is not...
This generator is more complete than the previous one, being able to generate pulses as indicated...