Found in a 90’s Electronics Now, this circuit has its output connected to an audio amplifier. The transducer is the type that fits on the finger to monitor the transparency and thus the beats.
So This circuit was published in a 1982 English magazine, but can be easily assembled using BC548 for...
With this circuit it is possible to tune an AM signal using a 5k potentiometer (4k7). The circuit was...
This power source was found in a 1968 Electronics World. The transistors are from that time. The...