We found these circuits in a Popular Electronics from the 90s. The circuit has a simple low power version and a higher power version with MOSFET (VMOS) of the time.
This circuit was found in Motorola documentation from 1966. The lamps are according to power and...
This circuit, which uses components still common today, was found in a 1997 documentation. It...
This circuit is intended to apply the music signal from a stereo to a telephone line for the...