Display

TM 11-6625-444-14-1

5-8. Display

b. The polarity signs + and - of tube V1 are

controlled by a flip-flop consisting of transistors

Q19, Q20, FET switches Q32, Q33, current source

a. The display (A14) circuits control the

transistors Q9, Q10, and associated components.

function/status indicators and the decimal in-

Inputs to this circuit are VDC, C POL INFO A

dicators associated with the readout tubes. The

and B and a. POL INFO A and B come from the

polarity detector in the A/D converter and

indicators are controlled by the respective func-

determine which of the two polarity characters are

tion control lines. They are illuminated when +5

illuminated. The range counter, through a,

volts dc is applied to the control line; however,

reverses the effects of POL INFO A and B as a

the control lines are interlocked in the associated

function of range to account for the fact that the

assembly so that the indicator remains ex -

polarity detector receives the input to the in-

tinguished unless the assembly is installed. The

strument in its true sense on the l-volt range, but

overrange indicator is operated by transistor Q5

in its inverted sense on all other ranges.

in the overrange driver circuit.