SCS-Silicon Controlled Switch

jojo September 16, 2009 2 Comments
Silicon controlled switch (SCS), like the SCR, is a unilateral, four layer three junction P-N-P-N silicon device with four electrodes namely cathode C, cathode gate Gx, anode gate G2 and the anode A, as shown in figure. Infact, the...
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GCS-Gate Controlled Switch

jojo September 16, 2009 1 Comment
As mentioned earlier, low-current drop out is the normal way in which the SCR is turned off. Gate-controlled switch is designed for easy opening with a reverse-biased trigger. A gate controlled switch (GCS) is closed by a positive trigger...
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Diac Applications

jojo September 16, 2009 24 Comments
The diacs, because of their symmetrical bidirectional switching characteristics, are widely used as triggering devices in triac phase control circuits em­ployed for lamp dimmer, heat control, universal motor speed control etc. Although a triac may be fired into the...
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jojo September 18, 2009 12 Comments
Introduction to Diac-Operation and Construction A diac is an important member of the thyristor family and is usually employed for triggering triacs. A diac is a two-electrode bidirectional avalanche diode which can be switched from off-state to the on-state for...
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SCR Applications

jojo September 15, 2009 36 Comments
The ability of an SCR to control large currents to a load by means of small gate current makes the device very useful in switching and control applications. A few of the possible applications for the SCR are listed...
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Full wave rectifier using SCR

jojo September 15, 2009 7 Comments
How to make a full wave rectifier using SCR ? For full-wave rectification two SCRs are connected across the centre taped secondary, as shown in figure-a. The gates of both SCRs are supplied from two gate control supply circuits....
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SCR as Half Wave Rectifier

jojo September 15, 2009 No Comments
How SCR functions as a Half Wave Rectifier ? SCRs are very useful in ac circuits where they may serve as rectifiers whose output current can be controlled by controlling the gate current. An example of this type of...
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SCR used as a Switch

jojo September 15, 2009 14 Comments
How an SCR functions as a 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...
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SCR Control circuits

jojo September 15, 2009 11 Comments
90° Phase Control of SCR. In ac circuits, the SCR can be turned on by the gate at any angle a with respect to the applied voltage. This angle α is called the firing angle. Power control is obtained by varying...
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SCR Protection Circuits

jojo September 14, 2009 1 Comment
How to protect an SCR using protection circuits ? SCRs are sensitive to high voltage, over-current, and any form of transients. For satisfactory and reliable operation they are required to be protected against such abnormal operating conditions. Because of...
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