We found this circuit in the November 1984 Radio Electronics magazine. The base frequency is given by C1. The power supply can be between 3 and 12 V.
This circuit is from a Radio Electronics magazine from August 1974. It used one of the first...
This circuit was found in an English magazine from 1973. The magazine no longer exists, but the...
This circuit for measuring very low currents was found in an American documentation from the...