This common circuit using operational amplifiers was found in the 1993 issue of Radio Electronics Special Projects. The circuit is sandwiched between the pickup and the amplifier input.
This circuit decodes a 1800 Hz tone used in communications. The circuit is from an American...
These two circuits were found in Radio Electronics magazine from February 1960. The transistor is a power...
With the development and availability of small LCD screens for automotive use, especially in...