Found in a Popular Electronics from the 90s, this circuit uses common components with several operational options, including the use of an optocoupler that allows its application in a shield.
Bis This two-transistor circuit was found in the January 1994 issue of Electronics Now magazine. The...
This receiver for the police band, which at the time was 45 MHz, was found in a publication by...
This circuit is the digital indicator for the previous circuit and can be used with similar...