Countdown Timer

Board layout.

This board uses a pair of CD4093 Schmitt-triggered NAND gates with RC oscillator as a time base and a CD4013 dual JK flip-flop to control timer start/stop and horn.

Can be connected to two latch boards to count down from up to 99 seconds.

Count rate adjustable.

Horn output may be connected to a relay for 120VAC horn.

Operates off of 5 to 15 volts.

Price: $75 per board. Please email me to purchase. Checks only.