Why does the SCR remain 'ON' even though the gate pulse is removed?

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SUMMARY

The discussion centers on the behavior of Silicon Controlled Rectifiers (SCRs) and their ability to remain 'ON' even after the gate pulse is removed. The SCR operates based on a two-transistor model, where the removal of the gate pulse does not lead to immediate current cessation due to the regenerative feedback mechanism that maintains conduction. In AC applications, the SCR turns off when the polarity changes, while in DC applications, it remains on until the circuit is interrupted. This behavior distinguishes SCRs from standard transistors, which do not exhibit this regenerative characteristic.

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Why does the SCR remain 'ON' even though the gate pulse is removed?

I understood the two transistor model but I want to know the bare physics of it. If you remove the gate pulse only the +ve anode w.r.t. cathode remains, thereby making junction J2 reverse biased hence current should fall of to zero value.

How does the SCR regenerate the current? Current flows from anode to cathode and electrons from cathode to anode(when it is in forward conduction mode). If we apply the principle of operation of SCR to transistor then when when we switch of base-emitter voltage current should flow but this doesn't happen in transistor and only in SCR..

Any help will be highly appreciated...!

Thanks.
 
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If you are using the SCR on AC it will turn off as soon the polarity changes, if you are using on DC it will stay on.
this is the equivalent of an electronic switch.
 

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