Overvoltage Indicator (CB22007E)

Using a CA3130 operational amplifier, this circuit drives an LED when the voltage exceeds the value set in VR1.

Metal locator (CB7883E)
Found in a 1966 documentation, this “coin finder” uses components from the era operating at 2.1...
High Pass Filter 741 (CB16119E)
This filter operates in the “opposite” way to the previous one (CIR8814), cutting all signals...
Stepper motor as encoder (CB21248E)
In the figure we have the way to use a stepper motor as an encoder. Operational amplifiers can be of...