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 circuit shown in the figure can be used as an indicator of presence and high voltage in a...
This circuit uses the 2N626, the first commercial Darlington transistor. We found it in Radio...
This circuit can generate signals from 80 to 800 Hz with an amplitude of 0.3 V. We find it in a...