This is a field strength meter found in an 80's Hands On. The circuit operates at frequencies up to 500 MHz and has a buzzer as its indicator. Can be used as a detector for spy transmitters.
This circuit indicates when the voltage of a 12 V battery is low. With changes, for example, the...
Any NPN general purpose transistor can be used on this simple AM radio. The coil consists of 100...
In the figure we show the typical configuration of a shared line using a twisted pair where the...