This flashlight project with a blinking light that makes it easy to find was found in the January 1990 issue of Radio Electronics magazine. The light uses a common light bulb.
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...