Contents
What is triac control?
A Triac is a high-speed solid-state device that can switch and control AC power in both directions of a sinusoidal waveform. Being a solid state device, thyristors can be used to control lamps, motors, or heaters etc.
How does triac control AC voltage?
As a triac is connected in an ac circuit, and if the load in the circuit is resistive, the triac turns off at the zero crossing points of the voltage in each half (the supply (input) voltage reaches zero at the end of each half cycle).
Is triac current controlled?
TRIACs are a subset of thyristors (analogous to a relay in that a small voltage and current can control a much larger voltage and current) and are related to silicon controlled rectifiers (SCRs).
How does a triac speed control circuit work?
How a dimmer / AC motor speed controller works? Triac controls the flow of alternating current to the load, switching between the conduction state and the cut-off state, during the positive and negative half cycles of power supply (110/220 VAC that comes from the electric outlet of our homes).
What is TRIAC and its working?
The triac is another three-terminal ac switch that is triggered into conduction when a low-energy signal is applied to its gate terminal. Unlike the SCR, the triac conducts in either direction when turned on. Triacs of 16 kW rating are readily available in the market.
How does the TRIAC phase control circuit work?
And because the Triac activates for only half the period, it proportionately cuts down the power being supplied to the load, by approximately 50% (Fig. 1). Thus, the amount of power to the load could be controlled at any desired level, merely by varying the triac triggering point on the AC phase waveform.
How are TRIACs used in solid state systems?
Triacs are popularly used as a solid-state replacement of relay for switching high power AC loads. However, there’s another very useful feature of triacs which allows them to be used as power controllers, for controlling a given load at a desired specific power levels.
What can DIAC be used for in TRIAC circuit?
The diac is most often used as a trigger device in phase-triggered triac variable power control applications, as in the basic lamp dimmer circuit of Figure 6.
What happens at the end of a TRIAC cycle?
The triac automatically unlatches at the end of each AC half-cycle as the instantaneous supply voltage (and thus the load current) briefly falls to zero.