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ΜΑ.909LoudspeakerAmplifier
Racal-TacticomLimited,Ñ,Ο.Βοχ º º 2,472 BasingsτokeRoad, Reading,Berks.RG2ooF.Tel. Reading (0734)83312. Telex: 848Ο1 1 Grams: TacticomReading.Prepared by Central HandbooksDepartment, RacalGroupServicesιimited.
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The ElectronicsGroupPrinted ßη England Ref. 3º θ lssue 3.1 1.78-25
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coNTENτs
ΙNTRODUCΤΙON
CONSΤRUCTΙON
CΙRCUΙΤDESCRΙPTΙON
TESΤΙNG A,ND FAULTLOCATΙON
COMPONENTSLIST
ΙLLUSΤRAΤΙONS
Circuiτ:ΙγÞΑ.909 LoudspeokerAmplifier
ComponentLoyout:ΙýΑ.909LoudspeokerAmplifier
Ņ̃ι
ι
ι
2
3
&.ι
2
tvlA.909 Confents
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_L_Q ,ñ_S_]P_EAKΕ Β_ ∆∆4_ιL|_F_¸3__υ_ΝιtΙγfJ=Jι∆*292
Ι NTRODUCTΙONANDOPERATIOΝl. The loudspeokerAmplifierUnitprovidesο loudspeokerfacilityfor ο rnonpack.
The power source for the unif is derived from the manpock.The οηΙγ operationrequired to bring the unit into use is to connect the plugοη the unit to one of the AUDIOsockets οη the rnonpack
CONSTRUCTlON2. The omplifier unitis ossembled ßη ο cost metol case as illustrated ßη Fig.2.
The cose is complefelywoterproof . The moiorityof the components of the unitore ossembled οηο printed circuitboord vvhichis mounted ιτßhßη the cose. The bock panelof the cose is removable, and is heldßη positionby four screu/s. Αsealing gasket is fittedbetιyeen the bock ponel and the cose.
CΙRCUITDESCRΙPΤΙON3. The circuit(Fis. l) consists ofο three tronsistor, transformerless poιrer
amplifier,designed to feed υñ to 5Φ mWinto α35 ohm lood. The pσ,verconsumptionof the amplifierat moximumoutput is approximatelyü0 mAfromοη Ι8ýοΙtsupply.
4. The input signol is applied to the base of ο η.ñ.η. transistorTRl,νßα thecapocitor Cl. TRIoperates os ο driver stage for the output transistors TR2ond
TR3connected ßη the compIementory symmetry mode, vlhichoperotes os follows:
5. TR2is α η.Ñ.η. type transistor, connected os αη emitter folto,aer ι^ιßh TR3providingthe emitter lood. ΤR3is α ñ.π.Ñ. type tronsistor connectedos οη
emitfer follolverιy,ith TR2octing as its emitter lood. TR2base ond TR3base ore bothconnected to fhe driver stoge output
ü. Οη the negotive portionof the input signalTR3conducts ond TR2is cut-off .Οη the porh of the signal ι,,rhichore positive TR2conducΕand TR3is cut-off .
Resistor R4 and diode Dlprovldebose bias for the output tronsistors, preventingcrossoverdistortion.DiodeDlhos α temperature choracteristic similorto the emitter-bose iunctionof α transistor, ond tends to compensote for resistance voriotionwith temperoture of TR2and TR3.
7, The octuoloutput ]ood is the loudspeakerιyhichis connected, νßα copocitorC4, το τhe emiττers TR2ολd TR3,and therefore posses current οη both holf
cyclesof the input signol.
ΙιΛΑ.909
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8. D.C.negative feedbock,whichstobilizesthe ιvorking voltageof the outputtransistor, is provided by resistor R§, connected between the commoι]emitter
iunctionof TR2ond TR3ond the bose of TRl. ResistorRllimihthe minimumvolue of sourceimpedonce.TESΤΙNGANDFAULΤLOCAΤΙON9. Το goin occes for testing or foult locotion remove the four scre\^/s ι̂ ιhßòh ore
locoted ßη the corners of the bock ponel. Ensure that the gasket is not dornoged,,yhen removing theponel.
Ιο. The omplifiercomponentboord is mounted οη pil|ors vvithinthe unit ond removalis self-evident.
Ιl. The followingtesf figures shouldbeobtgined vvithο serviceobleunit:
(q) SupplyVolmge- Ι8 volts(b) CurrentConsumptionι^ιßh ηο input signal - betιyeen ü ond Ι0 mA.(c) Currentconsumption οt fulloutput (500 mW) should be bet,,veen 59ond
ü5 mA.
ΝΟΤΕιThe omplifieris not connected to eorth.
'νlΑ.909
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Cct.Ref. Value Description
COMPONENTSLΙST
- Τοl. RocalKat' ο/ο ÑοττΝο.
RιR2R3R4R5
Resistors
Capocitors
òιc2
c3
c4
330Ω390Ωι .5κΩüα)5. üκΩ
*νγ ι0*νγ ι0*νγ ι0*νγ ι0*νγ ι0
35ν 2025ον ß13
ι üν ßß3
9ι 99039Ι99ο49ι 99089|98979199Ι4
9Ι4ν6
9ι üι 87
92Ι5¸
909γ279106829Ι 0ü8ι
906720
AD.700380AD.700487
9ιü258
Transistors
τRιτR2TR3
Diodes
Dι
Miscellaneous
CompositionCompositionCompositionCompositionComposition
Tanto lum
Ceramicon
Electrolytic
Ν. Ñ. Ν. SiliconΝ. Ñ.Ν. SiIiconÑ. Ν. Ñ. Silicon
Silicon
Czasket, loudspeakerGasket, back panel
Loudφeaker(35Ω)
4.7yF
.0Ι µF
Not Used
Ι ωµt
LSι
ΜΑ.909
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COMPONENΤSLΙST
Cct.Ref. Volue Description
- Τοl. RacalKat' ο/ο Parτ Νο.
Resistors
RιR2R3R4R5
Capacitors
Cl 4.7yFC2 ,0ΙµFC3 Not UsedC4 Ι ΦµF
Trons istors
ΤRιTR2TR3
Diodes
Dι,
Miscellaneous
CompositionCompositionCompositionCompositionComposition
Tontalum
Ceromicon
Electrolytic
Ν.Ñ.Ν.SiliconΝ.Ñ.Ν.SiliconÑ. Ν.Ñ. Silicon
SiIicon
Gasket, loudspeokerGasket, back ponel
Loudspeaker(35Ω)
330Ω390Ωι .5κΩü8ò)5. üκΩ
*νγ ι0*νγ ι0*γγ ι0ßνγ ι0*νγ ι0
9ι 99039199049ι 99089|9897919914
914Φ6
91ü187
921529
909φ79ι 0ü829ι 0ü8ι
9α6720
AD.700380AD.700487
9ιü258
35ν 20250ν ]13
ιüν :ß3
LSι
ΜΑ.909
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PLiΑ.7
ιιI
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Fig. 1
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_r/'
tr-σ ^σ",σ
2
vIEwνγιτΗBAc-ι(REMoVED
Fig.2
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ο Η g_ .'*'υ οο2 -j__l- f οι
ΜΑ.θ09LoudspeakerAmpiifier