Pioneer SX-3800 manual six-gaoo

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F	OverloadDetector
	The overload detector circuit incorporates the
	load (RL) in one side of a Wheatstone
T	bridge.The
	base and emitter of a sensingtransistor (e1) are
	connected to the opposite corners of the bridge,
	so if RL decreases,Q1 will becomeforward biased.
r	If RL falls below a prescribedvalue, e1 will turn
	on, thereby C1 will rapidly discharge.As conse-
	quence, Q4 will turr on and the relay will become
r	deenergized, thus causing the output circuit to
	open.
	DC VoltageDetector
	The output circuit is connectedto the e6 emit-
T	ler and Q5 base via a low-passfilter (Rg, C2).
	Any DC voltagesappearingthe output circuit of
	the porver amplifier, it wil] be applied to the e6
T	emitter and Q5 base.If the voltageis positive,eb
	turns on. C1 will rapidly dischargeIf. the voltage
	is negative,Q6 turns on. C1 will rapidly discharge.
T	As conseqnence,Q4 will turn on and the relay will
	become de-energized,thus causing the ourpur
	circuitto open.

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six-gaoo

Fig.4-13 Protectioncircuir

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