We found this circuit in the Linear Applications Handbook of the 1994 National Semiconductor. The transistor must be a high voltage type and the LM3900 power supply must be symmetrical.
This circuit controls the passage of the signal from an input to an output using a DC signal from a...
This amplifier with two transistors and unity gain was found in a 1974 Ferranti transistor manual....
Found in 1980s documentation, this circuit uses a small transistor radio output transformer and a double...