We found this circuit in a 1986 documentation. It uses only LEDs, batteries, resistors and the power supply which can consist of 4 batteries or a 9V battery. The basic circuit uses two-color LEDs.
November 2016 - The TL3780 ultra-miniature E-switch touch switches can now be obtained from Mouser...
Using a 4046 PLL this circuit was obtained from the October 1994 issue of Electronics Now...
Found in a 1968 US publication, it is a font filter. The transistor is according to the desired...