This DC motor control uses a power operational amplifier. We found it in December 1984 in the Radio Electronics magazine. The amplifier must be mounted on a heat sink and the maximum current is 1 A.
Found in the October 1992 Radio Electronics magazine, this oscillator is controlled by switch S1....
This circuit was obtained in a 1976 amateur radio manual. The circuit can be made with a 2N2222...
The component used in this circuit is not very common today as the circuit is from the 80's. It...