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The progression from Shockley diode to SCR is achieved with one small addition, actually nothing more than a third wire connection to the existing PNPN structure. If an SCR's gate is left floating (disconnected), it behaves exactly as a Shockley diode. It may be latched by breakover voltage or by exceeding the critical rate of voltage rise between anode and cathode, just as with the Shockley diode. Dropout is accomplished by reducing current until one or both internal transistors fall into cutoff mode, also like the Shockley diode. However, because the gate terminal connects directly to the base of the lower transistor, it may be used as an alternative means to latch the SCR. By applying a small voltage between gate and cathode, the lower transistor will be forced on by the resulting base current, which will cause the upper transistor to conduct, which then supplies the lower transistor's base with current so that it no longer needs to be activated by a gate voltage. The necessary gate current to initiate latch-up, of course, will be much lower than the current through the SCR from cathode to anode, so the SCR does achieve a measure of amplification. :) sorry its kinda hard to explain. I hope I helped

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9y ago
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11y ago

Because it is a rectifier.

However, it differs from other rectifiers in that it doesn't conduct until current is passed through the gate-cathode junction.

The conduction is therefore controlled.

The advantage over a normal rectifier diode is that the s.c.r. can be made to conduct at any point on a positive excursion of an applied a.c.

Once it conducts it will continue to do so until the applied voltage is almost at zero, at which point it turns off again.

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The term 'rectifier' dates back to the so-called 'War of the Currents', between Thomas Edison, an advocate for d.c. electrical systems, and George Westinghouse, an advocated for a.c. electrical systems. In an attempt to convince people that d.c. was the better system, Edison made a lot of use of language to promote his beliefs; one was to suggest that changing a.c. into d.c. was to 'rectify' it -that is, to change it into the better (d.c.) system! That term has stuck, and we have used it to describe the process of changing a.c. into d.c. ever since.

Another term Edison used to denigrate a.c. systems, which had by then been chosen to power electric chairs, was to describe death by electrocution as being 'Westinghoused'!

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11y ago

Silicon-controlled rectifiers are used in switching circuits, for phase control, for clipper circuits, inverting circuits, and relay-control circuits

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12y ago

The most common use of SCRs is in a bridge network for variable frequency motor drives.

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16y ago

how am i ment to know sorry

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0.3

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Q: What is the breakdown voltage of the silicon controlled rectifier?
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What is the forward biased knee voltage for a 1n4001 silicon diode?

A; The 1N4xxx series of rectifier diodes are specified as 1 amp forward conduction. the last number signify the maxi mun reverse voltage it can sustain without breakdown.


Why mostly a transister is used as amplifier than diode?

A diode is not an amplifier. It is a rectifier with asymmetrical voltage breakdown voltages. Usually the forward voltage is around 0.6V to 0.7V (silicon), and the reverse voltage is smaller than breakdown voltage, which is much higher. A transistor can be used as an amplifier, by taking into account the fact that the voltage breakdown curves vary, usually collector-emitter, as a function of some other current, usually base-emitter, but this depends on the class of the amplifier and whether or not the transistor is driven into saturation.


What is voltage regulation of a rectifier?

A: actually a full wave rectifier does not regulate. It will however follow the input minus diodes voltage drops. depending on current it is assumed to be .6 to .7 volts for silicon diodes.


Why the bridge rectifier is best?

What is the advantage of using the bridge rectifier A: NONE no advantage the only advantage can be considered it the fact it will provide more voltage but never more power actually less by a .7 volt diode drop


Why an op-amp diode rectifier called as a precision rectifier?

In a rectifier made of just diodes, the diodes have a voltage drop, resulting in a lower DC output voltage. By introducing an Op-amp, this voltage drop can be overcome. Since there is no voltage drop caused by the diodes, the rectified signal is not changed by the rectifier, so it is called a precision rectifier.

Related questions

How much is the reverse breakdown voltage of a 2P4M silicon controlled rectifierct?

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What is the voltage rating of silicon controlled rectifier?

It depends on the particular SCR. They make them in all different voltage ratings. Please specify the particular SCR you are interested in.


How do you use a thyristor as a diode?

A thyristor, also known as a silicon controlled rectifier, is a diode that can be turned on by application of a small gate voltage.


When An SCR conducts appreciable current?

And SCR will conduct appreciable current when it is gated "on" and thus "told" to conduct. A silicon controlled rectifier(SCR) is an electronically controlled DC switch, and the gate is the terminal to which the control voltage is applied. Use the link below to learn more.


What is the forward biased knee voltage for a 1n4001 silicon diode?

A; The 1N4xxx series of rectifier diodes are specified as 1 amp forward conduction. the last number signify the maxi mun reverse voltage it can sustain without breakdown.


Why does a rectifier diode is not operated in breakdown voltage?

The breakdown voltage of a diode is the minimum voltage at which it conducts in both directions. If you have a 100-volt rectifier diode (1N4002) and you wire it into a 110v circuit, it will flow current in both directions and you'll get no rectification.


Can zener diode used as rectifier?

Yes **************************************** Yes they can but there are pitfalls. A normal diode will have a high reverse breakdown voltage. A zener has a relatively low breakdown voltage (its "zener"voltage). If a zener diode is used as a rectifier it must have a zener voltage at least twice the peak of the applied a.c.


What are the advantages of a silicon-controlled rectifier?

SILICON CONTROLLED RECTIFIER APPLICATIONS i) Speed control for motors ii) Temperature control for electric hot plate iii) Dimmer switch for domestic lighting iv) Dimmer control for stage lighting.


What is the value of the knee voltage and breakdown voltage of z?

It is about 0.7 volt for Silicon diodes.


What is the firing angle of silicon controlled rectifier?

The SCR turns on based on gate voltage. The firing angle will depend on the point in the AC cycle where the gate voltage is where you want it, so the firing angle is a function of circuit design, not of the SCR.


How the breakover voltage is fixed for silicon controlled switch?

A: It is not fixed to any voltage. The manufacture test them as a sample on a lot and to have a specific breakdown it must not conduct within certain voltage applied. If it fail the testing the whole lot is rejected by default


Why mostly a transister is used as amplifier than diode?

A diode is not an amplifier. It is a rectifier with asymmetrical voltage breakdown voltages. Usually the forward voltage is around 0.6V to 0.7V (silicon), and the reverse voltage is smaller than breakdown voltage, which is much higher. A transistor can be used as an amplifier, by taking into account the fact that the voltage breakdown curves vary, usually collector-emitter, as a function of some other current, usually base-emitter, but this depends on the class of the amplifier and whether or not the transistor is driven into saturation.