Using 4 operational amplifiers this circuit generates 4 different tones. The circuit is from an American documentation from the 90's. Operational amplifiers are tTL084.
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...