- The SCR is made up of silicon and its operation as a rectifier can be controlled, hence the name given as silicon controlled rectifier.
- The basic construction of silicon controlled rectifier (SCR) is shown in above fig.
- The silicon controlled rectifier (SCR) is made up four layers of p and n type of semi conducting material. As a result there are three junction j1, j2 and j3. It has three terminals anode (A), cathode (K), and gate (G).
- The anode terminal is connected on the outer p-type material layer and cathode terminal is connected on the outer N-type material layer. Similarly, the gate terminal of the silicon controlled rectifier is connected on the inner P-type material layer which is nearest to the cathode type material layer, hence conventional silicon controlled rectifier (SCR) is also called as cathode gate silicon controlled rectifier (SCR).
- The semiconductor material layers are formed by the diffusion of lightly doped semiconductor material into highly doped semiconductor material.
