We found this circuit in the July 1988 Radio Electronics magazine. The frequencies are given by capacitor C1 and the voltage input is made at pin 1.
This differentiating circuit applies to any operational amplifier. It operates with the negative...
This circuit was found in a Motorola Manual of 1965. The circuit has neon lamps as trigger...
Figure shows the basic application of a data selector using the 4051 . The same configuration is...