This circuit is from 1994 documentation by National Semiconductor. What it does is convert the square root of a voltage to a proportional frequency.
Suggested by General Electric in 1965 documentation this circuit is intended for the 120 Vac...
This very high impedance circuit was found in documentation from the 1990s. The configuration can...
Found in the 1969 neon lamp documentation, using neon lamps this circuit provides 18 V regulated...