K0900E70 Datasheet, PDF (141/224 Pages) Teccor Electronics – Thyristor Product Catalog

Application Notes
AN1003
120VAC
(HIGH)
AC
(RETURN)
WHITE
R1
47
RV1
VARISTOR
C3
.1µF
R2
1M
D1
1N4001
D1
1N4001
2000 W
+5V
R3
20M
DECREASE HEAT
S1
S2
INCREASE HEAT
U1
VDD
VSS
GP5
GP0
GP4
GP1
GP3
GP2
12C508
R4
470
R5
470
VDD
D3
1N5231
C1
220µF
C2
.01µF
Q1
L4X8E5
R70
100Ω
Q2
Q4025L6
R6
470
Figure AN1003.24 Microcontroller Heater Control
Summary
The load currents chosen for the examples in this application
note were strictly arbitrary, and the component values will be the
same regardless of load current except for the power triac or
SCR. The voltage rating of the power thyristor devices must be a
minimum of 200 V for 120 V input voltage and 400 V for 240 V
input voltage.
The use of alternistors instead of triacs may be much more
acceptable in higher current applications and may eliminate the
need for any dv/dt snubber network.
For many electrical products in the consumer market, competitive
thyristor prices and simplified circuits make automatic control a
possibility. These simple circuits give the designer a good feel for
the nature of thyristor circuits and their design. More sophistica-
tion, such as speed and temperature feedback, can be devel-
oped as the control techniques become more familiar. A
remarkable phenomenon is the degree of control obtainable with
very simple circuits using thyristors. As a result, industrial and
consumer products will greatly benefit both in usability and mar-
ketability.
©2002 Teccor Electronics
Thyristor Product Catalog
AN1003 - 9
http://www.teccor.com
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