FLC21 FAMILY

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Rs

Ds

c

D

Th

Z

R

Ic

AC

MAINS

Ic

t

Fig. 2: BASIC AC MAINS APPLICATION

1/ IGNITION MODE

PHASE 1

The AC voltage is rectified by the diode Ds.

The ignition energy is supplied by the mains

and stored into the capacitor C.

c

D

Th

Z

R

Ic

Ic

t

Ds

DC/AC

Oscillator

Rs

Fig. 3: BASIC DC APPLICATION

PHASE 2

At the end of the phase 1, the voltage across the

capacitor C reaches the avalanche threshold of

the Zener diode Z. Then, a current flows through

this Zener diode into the gate of the thyristor Th

which is triggered.

The thyristor turn on generates an alternating

current through the capacitor C. Its positive parts

flow through the capacitor C, the primary of the HV

transformer and the thyristor Th. Its negative parts

of the current flow through C, D and the primary of

the H.V transformer.