Found in a 1970s documentation, this mini-organ toy circuit makes use of an integrated circuit from that time. This component is difficult to obtain today.
This 1 MHz oscillator was found in an Electronics World of 1969. The circuit uses a...
This circuit can be implemented with more modern operational amplifiers like the 741 and its...
This simple pole search or neon probe for the 110 V or 220 V power grid has nothing unusual, being...