DEFINITION AND TRIAC APPLICATION CHANGE

TRIAC is an electronic component whose operation is similar to SCR, sine wave output, MT1 Gate main terminal MT1, blower motor speed control, electric load, dimmer light, trigger, SSR (solid state relay) application.

TRIAC is an electronic component whose operation is similar to SCR (Silicon Controlled Rectifier). TRIAC comes from the word Triode for Alternating Current (three poles for alternating current). When SCR is connected to an AC voltage source or circuit, the output voltage will be rectified to DC. But on TRIAC, if it is connected to a signal or AC voltage source, the output will be in the form of a full sine wave (not rectified). TRIAC is designed to be used as an alternating current (AC) power control. TRIAC has three terminals namely Main Terminal 1 (MT1), Main Terminal 2 (MT2), and gate terminal (Gate).

TRIAC is likened to a series of two SCRs in one package which are connected in parallel with the opposite direction. The gate terminal in both SCRs is connected to one. Thus TRIAC is able to drain electric current from one of the terminals (feet) MT1 or MT2. Unlike the SCR, it will only drain an electric current from one of the terminals, namely from the anode to the cathode. The equivalent circuit of TRIAC with two SCRs is shown in the figure below.

The TRIAC gate terminal only requires a relatively low current to be able to control large AC current flows from both terminals (MT1 and MT2). TRIAC has four ways to do pentrigger on the foot as shown in the image below.

TRIAC output voltage can be changed to the average current used to load the load. The resulting waveform is still in the form of alternating current (sine) but the average current. Changes to the sine wave current will result in changing the power that is forwarded to the load.

TRIAC applications on electrical equipment include lamp dimmers and electric motor rotary speed control. In the field of cooling engineering, TRIAC is functioned as a controller for the blower motor speed at the indoor unit. TRIAC collaborated with an optocoupler that functions as a solid state relay. This circuit is very useful in areas where there are flammable materials because switching does not cause sparks. The blower motor speed control circuit is shown in the circuit below.

In Panasonic split AC units use the TRIAC BCR5PM and P360J optocoupler. The input signal comes from the microcontroller after passing driver / buffer. This is where motor blower speed split AC units are controlled with several different speeds. If the load is connected to an incandescent lamp, the brightness of the lamp will be different.

So many articles about TRIAC, hopefully it can be useful.

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