8250

Ultralong delay timer using two 8250 16-pin DIPs. The output is normally high when reset, and goes low upon application of a trigger input. It stays low for a duration of (100)² or 10,000 cycles. Total timing cycle for the two 8250s can be programmed from T_O = 1RC to T_O = 9999RC in 10,000 discrete steps by selectively shorting any combination of pins 1 through 8 from both units to the output bus (courtesy Intersil, Inc.).