Suggested by a 90s EDN, this circuit supports almost any LED as a source and a phototransistor as a detector. The circuit operates with a PLL 567 at a frequency of around 40 kHz.
The circuit bellow shows how four inverters [NAND, NOR or Inverters] Kim - This could be NAND,...
This circuit, from a 1978 publication, emits a modulated signal when the fine sensor is...
This commercial radio was manufactured in Japan in the 1960s. The circuit uses 4 transistors and...