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.
This circuit was found in a 1964 Electronic Design. The circuit can be implemented with equivalent...
This power control was found in a 1968 power circuit manual. The SCRs are according to the power of...
This first order filter that can be implemented with any operational amplifier was found in the...