Using 5 V relays, this circuit can be used as a control shield for microcontrollers. The circuit uses relays, and the motor voltage is independent of the control voltage.
This transmitter for the 2-meter range with a power of 1.5 W was found in a magazine 73 for radio...
The configuration shown in the figure is one of the most traditional when it is desired to produce...
This circuit operates according to the same principle as the previous one, but it has a difference in...