This dual-tuned 60 Hz oscillator was found in the Radio Experimenter Special projects of 1993. The circuit has the timing ranges given by C1 which can be changed.
This TTL decoder circuit for PC ports was found in a document from 1992. The power supply can be...
This circuit is from an old Popular Electronics, but it can be easily implemented nowadays, even...
The basis of this circuit is a CA3130 operational amplifier. The transistor can be BC548, and the...