Found in Popular Electronics from the 90's, this circuit uses 555 integrated and common transistors to generate two tones determined by push buttons S1 and S2.
This circuit was found in a 1964 Electronic Design. The components are of the time, and modern...
This circuit was found in a 1999 publication. Its purpose is to flash two LEDs according to the...
This circuit is from a Popular Electronics from the 90's. The circuit directly drives high power...