(2) Pins 1 and 2 are triggered by the stor-
quency counter counts 120,000 counts prior to
age display pulse (end of reading).
the storage display pulse which occurs at the
end of a reading. A down-signal is generated
(3) Pin 4 is on through the auto-range
similarly when the counter counts 10,000 or less
pulses before the storage display pulse occurs.
(4) Pin 3 is on from the bidirectional count-
er, U1 (on the signal conditioning board).
5-12. Auto and Manual Range-Circuit
c. To generate a down-pulse at U5, pin 8, the
following conditions must occur:
a. U1 (pins 1, 2, and 3) detects the presence
(1) Pin 10 must be on through the auto-
of 120,000 counts and drives buffer U2 (pins 4,
range switch, S2.
5, and 6). Pin 6 drives the following circuits.
(2) Pins 12 and 13 must be pulsed by the
(1) Q13 which lights the overload lamp.
storage display pulse.
(3) Pin 9 must be held on by flip-flop Ul,
(3) Pin 5 of U5.
pin 11 when the above occurs.
(4) Pin 11 is held on by bidirectional count-
b. U5 will produce an up-range signal at pin
(1) Pin 5 is turned on by a count of 120,000.
d. Flip-flop U1 is set by U4, pin 11, at the