This circuit digitally counts input pulses. The circuit from a November 1970 Radio Electronics uses unijunction programmable transistors. Note the counted pulse duration.
The transmitter shown can reach around 100 meters depending on the location and sensitivity of the...
This circuit was obtained from a 1978 Practical Wireless. It generates a low frequency, low...
Using the LM170 integrated circuit, this circuit was found in the May 1970 Radio Electronics...