This circuit is intended to detect when current flows through the opening of a car door. The circuit fires the horn for 90 seconds. The FET can be the BF245 and the NPN transistors can be the BD135.
The sensor of this circuit is an NTC and the indication is made on a common analog indicator, and...
This 1.2 to 32 V x 3 A regulator was found in an 80's EDN. The power components must be equipped...
This circuit turns off after a time that depends on C1. The circuit is from an Electronics Now...