Samsung SR-S25NTA - Page 35

8-10. PCB SUB Ass’ y (INVERTER PCB)
FUSE LF1
OV
| D3! D4
VARISTOFy
TNR471KT
ae C1! iD
41. EMI circuit
COMMON MODE NOISE is attenuated by CHOKE LFI, NORMAL MODE NOISE and D.C
RESISTANCE.
2. Rectifier circuit
Holding voltage is converted to DC voltage by BRIDGE DIODE.
It is ELECTROLYTIC CAPACITOR and composed of balance circuit
3. First starter circuit
The current converted to DC by C2 is charged to C3 through R3. When more than 35V is charged at (3, the
first switching operation is initiated by sending the current to BASE of Q through DAC R: and Ds maintain
enough potential difference between EMITTER and COLLECTOR of TRQ for easy first switching.
4. Switching circuit
Q2 becomes ON by the current from DAC and then, the current goes through Cs + C7 + Cs + CH
—TR(C — E). The current sent to PT) is held at PTs and by this holding current, Q2 maintains ON stteé.
Switching circuit is consisted when OSC COIL becomes saturated by line current, counter-electromitve force
occurs at PT3, electromotive force is held at PTz, and then, Qi comes to be operated.