Characteristics: Triac - nptel
Characteristics: Triac - nptel
Characteristics: Triac - nptel
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∫<br />
2<br />
i dt =<br />
∫<br />
-2<br />
10 2<br />
0<br />
( 1556 Sin 100 π t)<br />
( 1556)<br />
2<br />
∫<br />
-2<br />
10<br />
[ ]<br />
= 1 - Cos 200 π t dt<br />
2 0<br />
-2 2<br />
4 2<br />
= 1 × 10 ( 1556 ) = 1.21 × 10 A Sec<br />
2<br />
4. At the beginning of the turn on process the thyristor starts conducting through the area<br />
adjacent to the gate. This area spreads at a finite speed. However, if rate of increase of anode<br />
current is lager than the rate of increase of the current conduction are, the current density<br />
increases with time. This may lead to thyristor failure due to excessive local heating. However, if<br />
the contact area between the gate and the cathode is large a thyristor will be able to handle a<br />
di<br />
relatively large<br />
a<br />
without being damaged.<br />
dt<br />
The maximum<br />
dia<br />
dt<br />
will occur when the thyristor is triggered at ∝ = 90°. Then<br />
di<br />
L a<br />
= 2 × 220 Sin 90<br />
dt<br />
0<br />
Since<br />
di<br />
a<br />
dt<br />
6<br />
Max<br />
= 50 × 10 A Sec<br />
2 × 220<br />
-6<br />
L<br />
min<br />
= = 6.22 × 10 H = 6.22 μH<br />
⎛dia<br />
⎞<br />
⎜<br />
⎝<br />
dt ⎟<br />
⎠<br />
Max<br />
V C<br />
t off<br />
200 V<br />
v THM<br />
dv / dt<br />
t<br />
i C<br />
20 Amps.<br />
t<br />
Version 2 EE IIT, Kharagpur 38
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