This high impedance circuit was found in 1967 documentation by Ferranti. The original operational amplifier is from that time. The circuit can be implemented with modern equivalents.
The 78XX series voltage regulator integrated circuits do not support an input voltage greater than...
This is the complete circuit of a multimeter using a 50 uA instrument with a 2k coil. The circuit...
This circuit came out in a Popular Electronics from December 1995. It is a double T configuration that...