Found in an Electronics World of 1966 this circuit can be made with current power transistors. It causes colored lamps to flash to the rhythm of the audio signal applied to the input.
In the figure we have the circuit of a multi-range ammeter using a 50 uA full-scale instrument. The...
We found this circuit in a Radio Electronics magazine from December 1969. The circuit uses a...
This blocking oscillator was found in a publication from the 50's. The coils determine the...