This regulator can be controlled by a logic signal. The circuit is from an Electronics Now from the 90s. Note that the switching transistor is before the integrated circuit.
This circuit can be used at the same time as a preamplifier and voice by activating a relay when...
The circuit shown in the figure was found in a 1977 documentation, which can provide a good gain...
This circuit, which provides a power of up to 3.5 W, can be supplied with voltages from 9 to 14 V....