This circuit is from an American documentation from the 90s. The transistors are of power and must be equipped with good heat sinks as well as the integrated voltage regulator.
This circuit is from a 1979 documentation. The critical component is the CA3130 operational...
This circuit can be used with 3 receivers and is intended for low frequencies (medium wave range). We...
This circuit shows how to control a TTL logic gate with a phototransistor. The phototransistor supports an...