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 oscillator appeared in the September 1950 Radio Electronics magazine. The frequency is...
This multipurpose amplifier of a few hundred milliwatts of power was found in a Raytheon circuit...
This well-known configuration of the guitar effects pedal was obtained in an English magazine from...