Barrett 950 - Barrett 940 Man-Pack; Ancillary Components; To 240 VAC Input Charger Supply Barrett P;N BCA94012; Charge Regulator Suit 13 Ah Nimh Battery 12 V DC Input P;N BCA94021

BARRETT 900 SERIES TRANSCEIVERS
9.4 Barrett 940 man-pack - P/N BC94001
The Barrett 940 man-pack is technically identical to the Barrett 950 but has the PA set between 10 and
35 W output. In addition it is fitted with the high stability TCXO/DCXO as standard and has a switch
mode regulator fitted to the microprocessor PCB in place of the normal regulators for low power
consumption purposes. A connector transition PCB provides a microphone amplifier for the handset
connector and transition from the IDC cable to the military waterproof front panel connectors. The 940 is
constructed in a water resistant case and has a battery pack that clips on the rear of the transceiver. In its
portable form an accessory cover is provided that fits over the front panel when in transit.
The BCA94012 Input Charger Supply is an AC/DC switch-mode power supply that provides a regulated 16V
output from an AC power source of between 90V and 264V.
The BCA94021 NiMH 12V input charge regulator charges the BCA94008 battery with a constant current
source of approximately 2.5A. This source is regulated by U4:A, Q9 and R30. The source is pulsed or
switched off by the battery charge controller U3 using Q5. The current source is pulsed to look for a voltage
drop which indicates the battery is fully charged. The current source is switched off if the battery is fully
charged or a fault condition occurs. A fault condition is where the battery voltage is over 14.7V or under 7.4V
or where battery temperature is over 54C or under -9C. This temperature is measured by a thermistor inside
the battery pack.
The charging section is provided with power from two possible sources. The first is regulated external DC
input of 16V provided, usually, by a charger supply Barrett P/N BCA94012. This input is over-voltage and
reverse voltage protected by a relay. The second is unregulated DC input with an input range between 10.8V
and 15.6V. This is over-voltage, under-voltage and reverse voltage protected by a relay and supplies a
switch mode power supply to provide 16V to the charging section.
9.4.1 940 ancillary components
9.4.1.1 110 to 240 VAC input charger supply Barrett P/N BCA94012
9.4.1.2 Charge regulator suit 13Ah NiMH battery 12V DC input Barrett P/N BCA94021
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