We found this circuit in the March 1980 Radio Electronics magazine. The circuit used is the HA2400 released at the time. The power supply must be symmetrical.
This simple circuit causes an LED to flash at times whose active cycle is determined by C1 and C2....
In the figure we show the typical configuration of a shared line using a twisted pair where the...
This circuit appeared in Amateur Radio Today in an issue and was found in a 1995 issue. The...