This configuration can be applied to other operational amplifiers to increase the current capacity. The circuit is from the 80s. The transistors used are from that time.
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...