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Business travel charger circuit detailsDec 12, 2016

1. the oscillation circuit: the circuit consists of transistor VT2 and switch the transformer T1 and so on. After connecting the power supply, AC 220V by half-wave rectifier diode VD2, formed about 100V DC voltage. Switch the voltage transformer t, BU 1 transistor VT2 c is added to the primary winding, while the voltage starting resistor R4 VT2 b provides a forward bias voltage, the VT2 conduction. At this point, the transistor VT2 and switching transformers? T1 blocking circuit begins working, switch current through the t-1-1 in the primary winding of the transformer. Due to the positive feedback effect, winding induction voltage 1-2 of transformer t through feedback resistors R1 and capacitor C1 to VT2 b, b extremely turn-on current increase of transistor VT2, rapidly into the saturated zone. As the capacitor C1 voltage rises, VT1 b voltage decrease, by transistor VT2, and gradually withdraw from the saturated zone, their collector currents began to decrease, 1-1 magnetic flux generated in the primary winding of the transformer t-also began to decline. In a 1-2 the feedback winding induction voltage transformer t, VT2 rapid cut-off, completed a cycle of oscillation. VT2 cut-off during the transformer windings induces a t 1-3 5. AC voltage of 5V, as after the level of charging voltage.
2. the charger circuit: the circuit is composed of a soft plastic encapsulated integrated circuit IC1 (YLT539) and transistor VT3 and so on. 1-3-winding induction AC from transformer t voltage 5. 5V the diode VD3 rectifier, capacitor C3? filter, output of a DC-8. 5V voltage (without load), part of the voltage is added to transistor VT3 e. Another part to the soft plastic encapsulated integrated circuit IC1 (YLT539) 1 foot, for which? for a working power source. Integrated circuit IC1 starts working after power, in its 8-pin output low charged pulse, VT3 transistor breakover, DC 8. E 5V voltage begins to battery charging.