SCR ( Silicon controlled Rectifier) Working and Application

In  this article we will learn about the SCR (Silicon Controlled Rectifier) working and application .we will also learn about the construction of SCR (Silicon Controlled Rectifier). We will know that what is SCR and how it works. It is an electronic semiconductor device which is use to controlled various electrical quantity as per manufactured. SCR is a three Terminal device. It has three junctions and four layers.

SCR (Silicon Controlled Rectifier) working and application

 The working of SCR(Silicon Controlled Rectifier)  can be explain in 4 modes

 

 

SCR (Silicon Controlled Rectifier) Working and application Totally depend on these four mode working. According to these SCR working mode its application decide.

1) Forward blocking mode-

in this mode voltage is applied to anode and cathode and gate voltage is kept zero (VAk=+ve and Vg=0). When composite voltage is applied to anode with respect to cathode that junction J1 and J3 are in forward bias and at junction J2 is in reverse bias. SCR is in forward blocking state. At this time the gate signal is not applied. A depletion region is formed in junction J2 and no current flows from anode to cathode. According to see the figure a small current is flow which is called forward leakage current.

2) Forward conducting mode-

in this mode voltage is applied to anode and cathode and gate voltage is also applied (VAk=+ve and Vg= +Ve). When small amount of positive voltage is applied to gate terminal while positive voltage is applied at anode with respect to cathode junction J3 act as a closed switch and conduct a large value of forward current with small voltage drop. With applying the gate signal SCR change from forward blocking state to forward conducting mode and it is called latching. SCR (Silicon Controlled Rectifier) working totally depends on the forward conduction mode.

3) Reverse blocking mode-

when negative voltage ia applied to anode with respect to cathode junction J1 and J3 are in reverse bias but junction J2 is in forward bias. SCR is in its reverse blocking state, which act as an open switch. A small amount of reverse leakage current will flow through the device.

4) Reverse conducting mode-

 As the reverse voltage is further increased; at the reverse breakdown voltage avalanche breakdown occurred at junction J1 and J3.

SCR acts as a closed switch in reverse direction. A large value of current will flow through the circuit and due to which losses will generate in the form of heat. So these are SCR working and application.

SCR Construction and working Application.

 

For Better understand SCR ( Silicon Controlled Rectifier ) working and application we must need to know about the construction of SCR.

SCR full form is silicon control rectifier. It consists of 4 layer of P and N type semiconductor forming 3 P-N junctions. Material is silicon doped with P and N type impurities thus forming P and N type extrinsic semiconductor. According to see the figure 1 anode terminal is outside the P region and cathode is outside of the N region. T

SCR (Silicon Controlled Rectifier ) Application and Advantage

SCR( Silicon Controlled Rectifier)  Advantages

1. It can be control AC power.

2. Simple to control.

3. Turn ON gain is high.

4. Small in size and it is very cheap in cost.

5. It can switch large current with low losses.

6. It can be used of high voltage also.

7. Operation of SCR is very fast.

SCR ( Silicon Controlled Rectifier) Application

1. It is used of control of power. it

2. It is can be used as switch for switch purpose.

3. It can be used as a high voltage protection.

4. It can be used for Voltage regulation.

5. This is can be used in convertors also.

Hence these are SCR (Silicon Controlled Rectifier) working and application. If you will find any incorrect in above article you must comment below in comment box