This circuit was found in an English publication from the 70s, an article that teaches how to calculate instruments. The circuit is still current and can be built with an analog indicator of 100 uA.
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...