What is GTO (Gate Turn OFF Thyristor)?

In this tutorial we are going to learn about what is GTO (Gate Turn OFF Thyristor)

GTO – Thyristor use as ideal switches, It has capability to blocking several thousand volt in off state and conducting several thousand ampere in on state. GTO like an SCR can be turned on by applying +VE gate signal and GTO can be turn off by a –VE gate signal.

Construction of GTO – as per below image of GTO can see there is one extra N+. It has three junction and five layers which make the GTO construction. In this construction can see upper side anode and lower side have cathode and there is one gate terminal which is use for turn on and turn off by positive and negative voltage.

Symbol of GTO – Below are the GTO symbol can see which are look like SCR, only one difference there is two arrow at gate terminal, there is one arrow lower side and one is upper side.  In GTO, when give the positive supply then it will be ON & when give the negative supply then GTO become OFF and this is main difference of SCR and GTO.

Working of GTO By two transistor – In below circuit can see one PNP and one NPN transistor are connected back to back then it become GTO connection. Here is one gate terminal there is provide the positive supply & negative supply, when give the positive supply then PNP transistor gain will be reduce. We give the supply from anode which comes from emitter of PNP there is base current and then it comes at collector of NPN then it become collector current. Then both transistor will be ON and when give the negative pulse at gate then collector will be ripple which oppose to base current due to this GTO become OFF.

Application of GTO : It has high performance devices system use in below :

  1. Rolling mills
  2. Robotics
  3. Machine tools
  4.  Tracing purpose and adjustable frequency invertor.
  5. AC derive
  6. DC derive
  7. Induction heater

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