What is a thyristor and how does the Silicon controlled rectifier(SCR) operate

 

Chapter 7 of our Ebook covers that topic - http://www.allaboutcircuits.com/vol_3/chpt_7/index.html

 

a thyristor is a combination of 2 transistors(pnp and npn) connected back to back

 

In short, you can think of them as a controllable diode. We can choose whether it will conduct or not, when it is biased forward. However, when it conducts we can't shut it down, unless it is reverse biased.

 

However, when it conducts we can't shut it down, unless it is reverse biased.

Unless it is a gate turn off thyristor.

http://en.wikipedia.org/wiki/Gate_turn-off_thyristor

 

They didn't teach us that in uni. Well, it's always good to learn new stuff.