This sensitive receiver for the medium wave range was found in Radio Electronics magazine from December 1960. The circuit has a headphone output and is powered by just 3 V.
Found in a 1966 documentation, this “coin finder” uses components from the era operating at 2.1...
This filter operates in the “opposite” way to the previous one (CIR8814), cutting all signals...
In the figure we have the way to use a stepper motor as an encoder. Operational amplifiers can be of...