This circuit was found in a Popular Electronics of the 1990s. The sensor is a rotating mechanical system with a propeller-driven magnet to count pulses with a reedswitch.
Three LM158, LM258, LM358, or LM2904 operational amplifiers are used in this instrumentation amplifier....
The circuit shown in the figure consists of a phase shift oscillator and its components have been...
We found this circuit in a 1989 publication. Its purpose is to produce noise in the VHF or UHF...