Page 325 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

Advantage of SCR

• It can handle large voltage ,current and power.
• The voltage drop across conducting SCR is small .this will reduse the power dissipation in the SCR.
• Easy to turn on
• The operation does not produce harmonics.
• Triggering circuit are simple

• It gives noiseless operation at high efficiency.
Drawbacks of SCR
• It can conduct only in one direction, so it can control power only during the one half cycle of ac.
• SCR can not be used at high frequencies or perform high-speed operation .the maximum frequency of its
operation is 400 Hz.
• Gate current can not be negative
Application
• Controlled rectifiers

• Dc to dc converter or choppers
• Dc to ac converter or inverter ,
• Speed control of dc and ac moter
• fan speed regulators
• AC voltage stabilizers

Phase Controlled Rectifier

Phase-controlled rectifiers are circuits used in power electronics that enable the conversion of AC voltage to DC
voltage by regulating the firing angle of thyristors. Thyristors are semiconductor devices that can regulate the flow
of current by using a gate signal. Phase-controlled rectifiers are employed in a variety of applications, including
motor drives, heating and lighting control, battery chargers, and power supplies for electronic devices.
Classification of phase controlled rectifiers

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CITS : E & H - Electronics Mechanic - Lesson 199 - 204