This amplifier is from Motorola's 1990 Linear Databook. The circuit can be used with operating amplifiers with the same characteristics and the power supply must be symmetrical.
This circuit that uses potentiometer tuning, was found in a documentation from the 80's. The...
Another electronic ignition circuit for cars with positive ground. This circuit is from a Radio...
The MC4741 integrated circuit consists of four operational amplifiers similar to the 741 in a...