What does a SCR do?

An SCR (Selective Catalytic Reduction) system is a system installed on diesel vehicles to reduce harmful Nitrous Oxide (NOx) emissions. It works by injecting an automotive grade urea, or Diesel Exhaust Fluid (DEF) through a specially designed catalyst, into the exhaust stream of a diesel engine.

What is a electrical SCR?

A silicon controlled rectifier (SCR) is a solid state switching device which can provide fast, infinitely variable proportional control of electric power. Not only does this give maximum control of your heat process, but it can extend heater life many times over other control methods.

Is a SCR an electronic switch?

We have seen that SCR operates either in on-state or in off-state and no other state in between, that is SCR behaves like a mechanical switch. As such it is called electronic switch.

What does an SCR look like?

Starts here1:43What is an SCR? – YouTubeYouTubeStart of suggested clipEnd of suggested clip58 second suggested clipWelcome to GTV. Today I will be showing you what an FCR is and as the r is an acronym for siliconMoreWelcome to GTV. Today I will be showing you what an FCR is and as the r is an acronym for silicon controlled rectifier. And is commonly referred to as a thyristors.

How SCR turn off?

To turn the SCR off, a positive pulse is applied to the base of Q, turning it on. The anode current is diverted to the transistor. When the anode current falls below the holding current, the SCR turns off. The transistor is held on just long enough to turn off the SCR.

Why silicon is used in an SCR?

The first reason for using silicon for thyistors is that silicon is the ideal choice because of its overall properties. It is able to handle the voltage and currents required for high power applications. Additionally it has good thermal properties.

Where are SCR used?

Applications. SCRs are mainly used in devices where the control of high power, possibly coupled with high voltage, is demanded. Their operation makes them suitable for use in medium- to high-voltage AC power control applications, such as lamp dimming, power regulators and motor control.

What is SCR triggering?

SCR triggering method can be defined as, when the SCR is switching in forward blocking state to forward conduction state which means OFF state to ON state, then it is termed as SCR turn ON methods or SCR triggering.

How can SCR be commuted?

The turn OFF process of an SCR is called Commutation. The anode or forward current of SCR must be reduced to zero or below the level of holding current and then, A sufficient reverse voltage must be applied across the SCR to regain its forward blocking state.

How many terminals are there in SCR?

3 terminals
Background: A silicon controlled rectifier (SCR) is a four-layer solid state current controlling device with 3 terminals. They have anode and cathode terminals like a conventional diode and a third control terminal, referred to as the Gate.

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