Samsung SCX-4500 Service Manual page 33

Product specification and feature
4) FUSER AC POWER CONTROL
Fuser(HEAT LAMP) gets heat from AC power. The 'ON/OFF control' is operated when the gate of the Triac is turned
on/off by Phototriac (insulting part).
In other words, the AC Controller is passive circuit, so it turns the heater on/off with taking signal from engine Controller.
When the 'HEATER ON' signal is turned on at engine, the LED of Photo Triac takes the voltage and flashes.
From the flashing light, the Triac part (light receiving part) takes the voltage, and the voltage is supplied to the gate of
Triac and flows into the Triac. As a result, the AC current flows in the heat lamp, and heat is occurred. On the other
hand, when the signal is off, the photo triac is off, the voltage is cut off at the gate of Triac, the Triac becomes off, and
then the heat lamp is turned off.
- Triac feature :16A, 600V SWITCHING
- Phototriac Coupler
Service Manual
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Samsung Electronics