This circuit was found in a Motorola manual from 1968. As it can be obtained 20 V at 15 kHz from 120 V x 60 Hz. The components are of the time.
In this amplifier, the supply voltage is 35 V and the input resistance is 2k2. Equivalent...
This high speed laser diode driver was found in a 1980s documentation. Power FETs can be replaced...
This instrumentation amplifier with differential inputs was found in documentation from the 90s....