Poptronics recommends this circuit for use in the car when the headlights are left on. The circuit uses a sensitive relay with contact current according to the headlights.
This transistor amplifier with complementary symmetry configuration can provide approximately 1 W...
This ultra-simple meter uses an output transformer and a small speaker as a microphone. The...
The integrated circuit used in this 80's application is very hard to find today. The circuit is of an...