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.
In the same way that we can regulate the voltage in the positive branch of the circuit, we can...
Based on the MC1488 or MC1489 operational amplifiers, this circuit has a 5000V isolation driving a...
Found in the July 1968 Supertena Bulletin of a Popular Electronics, this receiver makes use of the...