This circuit was found in the August 1972 issue of Radio Electronics magazine. The circuit generates 4 types of signals as can be seen in the diagram. The maximum frequency is around 20 kHz.
This simple operational amplifier tester was published in the November 1987 issue of Radio...
This squelch or silencer for receivers for the 11-meter band was found in the November 1971 issue...
This reader with TTL logic compatible output uses an LM139 comparator. The circuit was found in...