Information about Silicon Control Rectifier (SCR)

[ervie_3525]

GREETINGS!!!
I am a 4th year ECE student here in the Philippines. Can anybody help me with my report about Silicon Control Rectifier? Thanks ahead..

 

[kazemi]

SCR

It has the same charactaristics as the diode, current flowing from cathode to anode, when the anode is positive with respect to the cathode.
However, it will only do this when the gate is also positive with respect to the cathode.
In the circuit, with the switch open as shown, no current flows.
When the switch is closed, the diode begins to conduct and current flows from cathode to anode.
There is a problem.
If the switch is now opened, current continues to flow.
Conduction can be stopped by removing the the cathode/anode voltage.
Another method of stopping current flow is to reverse the polarity of the cathode/anode voltage.
If the thyristor is used with an ac supply then it will conduct on the positive half cycles and automatically switch off during the negative half cycles.
The resistor in series with the gate connection limits the gate current to a safe value.
you can see the folloing URL
en.wikipedia.org/wiki/Thyristor

 

[the_risk_master]

Re: SCR

Hi Ervie pards,


I totally agree with Sir Kazemi;
here are some usefull info I know I can share:

A silicon-controlled rectifier (or semiconductor-controlled rectifier) is a 4-layer solid state device that controls current flow. An SCR can be seen as a conventional rectifier controlled by a gate signal. It is a 4-layered 3-terminal device. A p-type layer acts as anode and an n-type layer as a cathode; the p-type layer closer to the n-type(cathode) acts as a gate.

Modes of operation:

In the normal 'off' state the device restricts current flow to the leakage current. When the gate to cathode voltage exceeds a certain threshold, the device turns 'on' and conducts current. The device will remain in the 'on' state even after gate current is removed so long as current through the device remains above the holding current. Once current falls below the holding current for an appropriate period of time, the device will switch off.

If the applied voltage increases rapidly enough, capacitive coupling may induce enough charge into the gate to trigger the device into the 'on' state; this is referred to as dv/dt triggering. This is usually prevented by limiting the rate of voltage rise across the device, perhaps by using a snubber. dv/dt triggering may not switch the SCR into full conduction rapidly and the partially-triggered SCR may dissipate more power than is usual, possibly harming the device.

SCRs can also be triggered by increasing the forward voltage beyond their rated breakdown voltage, but again, this does not rapidly switch the entire device into conduction and so may be harmful so this mode of operation is also usually avoided. Also, the actual breakdown voltage may be substantially higher than the rated breakdown voltage, so the exact trigger point will vary from device to device.


I hope pards these info helped you and dont forget to push the "Helped Me" button huh.

Taga UE ka cguro

 

[roykyn]

Re: SCR

try google search.... u ll get all animated stuff ...like wise it is easy to understand.....

 

[nguyennam]

Re: SCR

Google is our very good friend.

Or you can surf directly within the www.st.com (ST company), www.irf.com (IRF company), www.philips.com (Philips company) to pick out some very good document about SCR as they all are the very famous SCR manufacturers.

nguyennam

 

[leonzam]

Re: SCR

see

**broken link removed**

and

https://www.americanmicrosemi.com/information/tutorial/index.php?t_id=10