V-I Characteristics of SCR

V-I Characteristics of SCR

Ø Forward Characteristics 

When anode is +ve w.r.t cathode the curve between V &I is called Forward

characteristics. OABC is the forward characteristics of the SCR at Ig =0. if the supplied voltage is increased from zero point A is reached .SCR starts conducting voltage across SCR suddenly drops (dotted curve AB) most of supply voltage appears across RL

Ø          Reverse Characteristics

When anode is –ve w.r.t cathode the curve b/w V&I is known as reverse characteristics reverse voltage come across SCR when it is operated with ac supply reverse voltage is increased anode current remains small avalanche breakdown occurs and SCR starts conducting heavily is known as reverse breakdown voltage.

Ø           Application

ü               SCR as a switch

ü               SCR Half and Full wave rectifier

ü               SCR as a static contactor

ü               SCR for power control

ü               SCR for speed control of d.c.shunt motor

ü               Over light detector