This circuit simulates the effect of an inductance. Equivalent operational amplifiers can be used, and the power supply must be symmetrical. The circuit is from a 90's Poptronics.
This simple oscillator is yet another of the many versions of sonic insect repellent that we find...
The circuit in the figure operates at frequencies from 4 to 20 MHz and also uses a common junction FET...
This TTL counter was found in the April 1979 issue of Radio Electronics magazine. The circuit is...