POWER SUPPLY AND REPLY EVALUATOR

T.O. 12P4-2APX-192

NAVAIR 16-35TS1843-1

TM 11-6625-1646-25

preventing A3Q3 from charging A3C4 and disabling the

pulse, is routed to a monostable multivibrator (A4Q7 and

operation of the Monitor mode reply evaluator. A3Q7 will also

A4Q8). A4Q8 is normally on with A4Q7 being normally off.

be provided a low impedance path to ground, causing A3Q7 to

When the negative-going pulse is applied to the collector of

conduct. The test gate input from the mode generator at the

A4Q7 and the base of A4Q8, A4Q7 is turned on and A4Q8 off.

base of A3Q7 is amplified and inverted. The inverted gate is

The output of A4Q7 developed across A4R25, is +5 volts in

applied to a three input NAND gate (A4A3C, pins 4 and 5) in

amplitude and 0.35 usec in width. The positive-going 0.35

the comparator-decoder module (A4). The output of the

usec pulse is applied to decoding gate A4A3A, pin 9. Also

NAND gate is then routed to the In-Flight test reply evaluator.

applied to the three input NAND gate is the 19 usec negative-

5-31. In the In-Flight test reply evaluator, with no signal

going gate (paragraph 5-27) from A4A2 at pin 10 and the

applied, A3CRll is back biased by +5 volt allowing A3C8 to

power monitor trigger pulse at pin 11 (paragraph 5-26). The

charge through A3R21 and A3RT1 driving A3Q9 into

bracket spacing is decoded when the 19 usec negative gate is

conduction. This action sets the Schmitt trigger so that A3Q10

gone and the power monitor trigger pulse coincides with the

is on and A3Qll is off, back biasing A3CR12 of the time enable

0.35 usec pulse. A negative-going pulse is developed and is

OR gate by 12 volts, preventing operation of the lamp driver

applied to the output pulse shaper A4A4, a monostable

network. When an input pulse is applied, the back bias is

multivibrator. A4A4 generates a 0.45 usec pulse which, along

removed from A3CRll allowing A3C8 to discharge. At the end

with the high output of A4A6 and the high output of the

of the pulse A3CRll is back biased and A3C8 charges again at

frequency power comparator, is routed to the output enable

a rate that produces a. sawtooth waveform. When the input

NAND gate A4A3B, pins 1, 2, and 13. The negative-going

interrogation rate is at least 80 percent of the 400 PRF internal

pulse output of A4A3B is routed to pulse shaper A4A5, a

interrogation, the D.C. level of the sawtooth waveform will

monostable multivibrator. The positive 25 usec high output of

lower sufficiently to cutoff A3Q9, causing the Schmitt trigger to

A4A5 is routed to a three input NAND gate A4A3C, pin 3. The

abruptly change states, removing the back bias on A3CR12.

output of A4A3C is then applied to A3Q3.

5-32. In the lamp driver circuit, A3CR12 and A3CR13 (lamp

5-29. POWER SUPPLY AND REPLY EVALUATOR (A3) (See

enable OR gate), are normally back biased allowing A3Q12 to

figure FO-4). The input to the Monitor mode reply evaluator, a

conduct. This keeps A3Q13 off which removes the ground

negative-going 25 usec pulse, drives the base of A3Q3

circuit for the base of A3Q14 and keeps the lamp switching

towards zero cutting off A3Q3. This allows A3C4 to charge

transistor A3Q14 and indicator lamp off. When either A3CR12

through A3Rll for the duration of the pulse. A3C4 charges to

or A3CR13 are forward biased, A3Q12 is turned off allowing

approximately 0.3 volts during this 25 usec period. At the end

A3Q13 to conduct. This provides a low path to ground for the

of the 25 usec period A3Q3 is turned on, back biasing A3CR7

base-emitter junction of A3Q14 allowing A3Q14 to conduct for

and holding the charge on A3C4 constant. When the next

the duration of the forward bias state of A3CR12 or A3CR13,

pulse is received, the process is repeated with the charge

and providing 28 volts for illuminating the TEST lamp.

produced being added to the charge already present on A3C4

5-33. POWER SUPPLY (See figure FO-4). The power supply

from the previous pulse. After seven or more consecutive

for the TS-1843A is a combination series hunt type voltage

pulses occur at a repetition rate of 100 pulses per second, the

regulator with two outputs of +12 and +5 volts. Transient

voltage at the emitter of unijunction transistor A3Q4 will be

diode A3CR1 is located at the input of the power supply and

sufficient to trigger A3Q4, discharging A3C4 and generating a

has a dual purpose function. A3CR1 clips any negative

pulse across A3R17. With the monostable multivabrator in the

transient through ground and prevents any voltage above +36

state of A3Q5 on and A3Q6 off, diodes A3CR6 and A3CR8 are

v from entering the power supply. The control amplifier, A3Q2

back biased allowing A3C4 to charge as described above.

is normally on, holding the voltage across the 11.8 volt zener

When a pulse is applied to the emitter of A3Q5 and A3Q6,

diode, A3CR3 and the base of A3Q1 to approximately zero.

A3Q5 is turned off and A3Q6 is turned on. When A3Q5 is

When either the RAD TEST-MON switch or one of the mode

turned off A3CR6 is forward biased through A3R12 and A3R19

switches are depressed, the switch lead to the power supply is

preventing any incoming pulses from affecting A3Q3. A3C5 is

grounded through a diode in each switch lead, grounding the

also allowed to charge through A3R12 and A3R19 until the

base of A3Q2. A3Q2 is then turned off and allows the voltage

charge across A3C5 is sufficient to trigger A3Q4 again through

across A3CR3 to rise to approximately 13 volts. Shunt diodes

A3CR8. When A3Q6 is turned on A3CR13 of the lamp enable

A3CR4 and A3CR5 compensate for temperature changes in

OR gate will be forward biased for a minimum of two seconds.

A3Q1 and A3Q2 as well as compensating for the voltage loss

When A3Q4 triggers for the second time, a pulse is generated

across the emitters of A3Q1 and A1A2Q1. With 13 volts

across A3R17 which re-sets A3Q5 and A3Q6 to their original

applied to the base of A3Q1, A3Q1 is allowed to conduct. The

states as well as back biasing A3CR6 and A3CR8. This action

output at the emitter of A3Ql is approximately 12.5 volts and is

will also back bias A3CR13 of the lamp enable OR gate.

applied to the base of AlA2Ql causing AlA2Ql to conduct, +12

5-30. When any of the mode selector switches on the Control

volts is then available at the emitter of AlA2Q1l. The +12 volts

Unit are depressed, a high input is applied to the base A3Q8,

is routed to A3R4 where

causing A3Q8 to conduct. With A3Q8 conducting, a low path

to ground through A3CR10 is provided for A3Q3, thus

5-6