- Anonymous7 years agoFavorite Answer
Although SCRs have several ratings, the following are ones which are important from the subject point of view:
1. Forward breakover voltage. It is the voltage at which the SCR is switched from its OFF position to ON position. Its value is maximum for zero gate current. Commercially available SCRs have a forward breakover voltage ranging from 50 to 1200 V.
2. Holding current. It is the value of anode current below, which the SCR switches from its ON position to OFF position under the given conditions. In other words, holding currentis the minimum value of current required to maintain conduction.
3. Gate trigger current. It is the value of anode current necessary to switch SCR from its OFF position to ON position under specified conditions.
4. Average forward currents. It is the maximum continuous value of anode current, which the SCR can handle in its ON position under specified conditions. It is also called current rating. Commercially available SCRs have a current rating ranging from 1 to 1800 A.
5. Reverse breakdown voltage. It is the value of reverse voltage from cathode to anode at which the device breaks into avalanche region and starts conducting heavily.