This circuit generates a constant current given by R1. The load is on the high side of the feed (High Side). The circuit admits equivalent operationals and the source must be symmetrical.
Found in Popular Electronics this circuit will trigger a buzzer if the ignition key is removed...
Found in Popular Electronics, this sophisticated short-wave receiver requires a lot of skill from...
This circuit is from an old American documentation using LEDs in the rectification. The circuit...