This circuit, with printed circuit board, is from an article in Radio Electronics magazine from May 1971. The circuit uses the C106 which was already a common component at the time.
The sensor in this circuit is a BA315 diode. Other diodes can be experimented, but this is one...
The figure shows how to implement the AND function with a Norton LM3900 operational amplifier. The number of...
A single high-power transistor MJ15003 is used in the circuit in the figure to generate strong...