The Thyristor

The Thyristor
The thyristor is a semiconductor controlled rectifier (SCR)
used in power electronics. It consists of FOUR
semiconductor layers, i.e. there are THREE pn-junctions.
The three terminals are called
Anode (greek: Anodoz = upwards)
Cathode (greek: Kaqodoz = downwards)
Gate (sometimes called “base”)
The figure below depicts the thyristor's layers, whereas the
inner two layers are weakly doped.