A TRIAC is a three terminal device that can operate an AC load, either in On-Off mode, or in modulated mode, such as in a lamp dimmer.
The three terminals are M1, M2, and Gate. The AC source and load are connected in series with M1 and M2. If the Gate is held near the voltage of M1, the device does not turn on. If the Gate voltage is towards the direction of M2, the device turns on. Once the device turns on, it stays on for the duration of that line cycle, i.e. until the voltage between M1 and M2 reverses.
The actual trigger point varies depending on the specific device, so you need to look it up in the specifications for the device.
Note that the positive going trigger point is often not the same magnitude as the negative going trigger point. This can cause asymmetry in the output power, leading to a DC bias that is often not desired. Most designs compensate for this by providing another TRIAC operating in DIAC mode (or just a DIAC) in series with the Gate.
The DIAC is simply a TRIAC with the Gate connected to M2. This mode will trigger based on M2, rather than on Gate, and is symmetrical. Using a DIAC as the trigger for a TRIAC will balance the output waveform, minimizing DC bias.
If you design the controlling circuit so that the trigger point in the cycle is adjustable, you get a variable voltage switch, i.e. dimmer, that can be used for various things. The advantage of this over a rheostat, is that the TRIAC is fully conducting when it is turned on, so the power dissipated by it is relatively small, because the voltage differential is small, whereas a rheostat would need to dissipate at least half the expected power of the load.
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Bidirectional gate controlled thyristor similar to an SCR, but capable of conducting in both directions. Provides full wave control of AC power.
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SCR (Silicon Controlled Rectifier) ... (electronics) A semiconductor rectifier that can be controlled; it is a pnpnfour-layer semiconductor device that normally acts as an open circuit, but switches rapidly to a conducting state when an appropriate gate signal is applied to the gate terminal. Abbreviated SCR. Also known as reverse-blocking triode thyristor.
TRIAC is the word derrived from the 2 words TRIode and AC.
a circuit diagram consist of diac&triac
A gateless triac is a diac. It is often used in the gate circuit of a triac to balance out the firing voltage for the triac in both quadrants, so that there is no DC offset in the controlled load. This is because, while the gate trigger voltage is often asymmetric in the two quadrants, the M1/M2 breakdown voltage is often symmetric.
b for silicon
A: TRIAC will break over and conduct at a certain if a certain voltage is reached. That voltage depends on all different triacs devices
Triac-Lautrait's population is 454.
The diac and the triac are used to control the AC lines. The difference is that triac are bigger than diac.
The area of Triac-Lautrait is 6,400,000.0 square meters.
Triac is Three Layered Device . Emitter ,Collector and Gate
triac act as a ac contactor
TRIAC is the word derrived from the 2 words TRIode and AC.
a circuit diagram consist of diac&triac
How_is_triac_operated
A gateless triac is a diac. It is often used in the gate circuit of a triac to balance out the firing voltage for the triac in both quadrants, so that there is no DC offset in the controlled load. This is because, while the gate trigger voltage is often asymmetric in the two quadrants, the M1/M2 breakdown voltage is often symmetric.
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b for silicon
An SCR is a rectifier and can only conduct in one direction (half wave).A Triac can conduct in both directions (full wave).