Skip to main content

What is a Triac? How does a triac work?


What is a Triac?
Triacs are electronic elements that are wide utilized in AC power control applications. They are ready to switch high voltages and high levels of current, and over each elements of an AC wave form. This makes triac circuits ideal to be used in a variety of applications wherever power switching is required.
One specific use of triac circuits is in light dimmers for domestic lighting, and that they are utilized in several different power control situations together with motor control and electronic switches.
As a result of their performance, triacs tend to be used for low to medium power electronic switching applications, leaving thyristors to be used for the very heat duty AC power switching applications.
How does a triac work?
Before looking at how a triac works, it helps to have an understanding of how a thyristor works. In this way the basic concepts can be grasped for the simpler semiconductor device and then applied to a triac which is more complicated.
For the operation of the triac, it may be imagined from the circuit image that the triac consists of two thyristors in parallel however around other ways. The operation of the triac will be looked on during this fashion, though the particular operation at the semiconductor level is rather additional complicated.
Triac applications
Triacs are used in many applications. These electronic components are often used in low to medium power AC switching requirements. Where large levels of power need to be switched, two thyristors / SCRs tend to be used as they can be controlled more easily.
Nevertheless triacs are widely used in many applications:
Lighting control - especially domestic dimmmers.
Control of fans and small motors.
Electronic switches for general AC switching and control
There are naturally many other triac applications, but these are some of the most common.
In one specific application, Triacs will be included in modules known as solid state relays. Here an optical version of this semiconductor device is activated by an LED light source turning the solid state relay on according to the input signal.
Typically within solid state relays, the LED light or infrared source and the optical triac are contained within the same package, sufficient isolation being provided to withstand high voltages which may extend to hundreds of volts or possibly even more.
Solid state relays are available several forms, however those used for AC switching may use a triac.
Advantages of Triac
It may be triggered with positive or negative polarity of gate pulses.
It requires only a single heat sink of slightly larger size, whereas for SCR, two heat sinks should be required of smaller size.
It requires a single fuse for protection.
A safe breakdown in either direction is possible except for SCR protection ought to be with parallel diode.
Disadvantages of Triac
They are not much reliable compared to SCR.
It has (dv/dt) rating lower than SCR.
Lower ratings are available compared to SCR.
We need to watch out regarding the triggering circuit because it is triggered in either direction.

Labels:

Comments

Post a Comment

Popular posts from this blog

Different types of Limit Switches

Rotary Geared Limit Switches The operating of the Limit Switch is to prevent the mechanism or drive at the intense forward/reverse positions. The Limit Switches are significantly suited to use on reversing drives like a hoist, winches, rolling mills and various other mechanisms used in steel plants such as coke ovens, feeding machinery, valve drives etc. The contacts of Limit Switches are forty amps rated ceaselessly at 500 Volts A. C. The Limit switch is often supplied with two NC contacts or four NC contacts or (2 NO + two NC) contacts as per the need. For Series Limit Switches are shields are provided. The frequency of switching of each contact is suitable for a maximum of 720 operations per hour. The speed of the driving shaft rotation shouldn't be over 60 rpm. Features:- High durable standards Optimum performance Easy to install Counter Weight Limit Switches A metal structure offers the required stability to Counter Weight Limit Switches that job on heavy c...
Post a Comment
Read more

Solid State Relay AC & DC Input Circuit

Solid State Relays are semiconductor equivalents of the mechanical device relay and may be accustomed control electrical masses while not the utilization of moving parts. a normal electro-mechanical relay, SSR’s provide complete electrical isolation between their input and output contacts with its output acting as a conventional electrical switch in that it has very high, almost infinite resistance once nonconductive (open), and a really low resistance once conducting (closed). Solid State Relays can be designed to switch both AC or DC currents by using an SCR, TRIAC, or switching transistor output instead of the usual mechanical normally-open (NO) contacts. Solid State Relay DC Input Circuit When utilizing mechanical contacts, switches, push-catches, other hand-off contacts, and so forth, as the initiating signal, the supply voltage utilized can be equivalent to the SSR's base information voltage esteem, though when utilizing strong state gadgets, for example, trans...
Post a Comment
Read more

What is an Op-Amp? Operation, parameters & characteristics

What is an Op-Amp? Operational amplifiers are linear devices that have all the properties required for nearly ideal DC amplification and are therefore used extensively in signal conditioning, filtering or to perform mathematical operations such as add, subtract, integration and differentiation. An Operational Amplifier, or op-amp for short, is on a very basic level a voltage intensifying gadget intended to be utilized with outside criticism segments, for example, resistors and capacitors between its yield and information terminals. These input parts decide the subsequent capacity or "activity" of the enhancer and by ideals of the diverse criticism setups whether resistive, capacitive or both, the intensifier can play out a wide range of tasks, offering ascend to its name of "Operational Amplifier". Op-amp operation The amplifier’s differential inputs contains a non-inverting input with voltage (V+) and an inverting input with voltage (V−). Ideally, an op...
Post a Comment
Read more