The circuit shown was found in the February 1994 issue of Electronics Now magazine. The circuit records messages for a few seconds and plays them back as keys are selected.
This oscillator has its frequency controlled by crystal and its frequency can be between 100 kHz...
This small crystal microphone transmitter was indicated in an 80s spy book. The range depends on...
The circuit shown is from the 1994 Linear Applications Handbook by National Semiconductor. The...