This circuit is from the Texas Instruments operating amplifier manual. Any operational can be used and the font need not be symmetrical. Rf and Rg determine the gain of the circuit.
This high-gain amplifier was found in the March 1994 issue of Electronics Now magazine. The...
This circuit was found in American documentation from the 90's. The transformer is of the high...
The pulses produced in the small speaker or phone of this circuit have a frequency determined by...