[time-nuts] precision timing pulse

Chuck / Judy Burch ciandjaburch at gmail.com
Tue Nov 15 13:57:10 EST 2016

I'm building a laboratory scintillation counter that uses my HP 5335a 
counter as a read-out.  The FREQ mode gives only approximate results 
(maximum gate time is about 5 seconds).  The TOT mode counts pulses for 
an arbitrary time that can be set using the "external arm input" on the 
rear panel.  So I need a timing pulse (of either polarity) of known and 
adjustable width (time).  One way to do this is with a PIC frequency 
divider taking the counter 10MHz output down to 1 PPS following that 
with two or three ripple counters to get a 1 - 5 - 10 - 50 ... 
sequence.  That I understand.

How do I get a pulse to start with a push button and then stop for 
example 500 or 10,000 seconds later?

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