Protection has assumed a large importance in the power industry in the recent years. This protection involves the use of relays on a large scale. Relays are basically used to give commands to circuit breakers, contactors, etc by sensing different parameters like current, voltage, etc. Just as electrical circuits may range from a few watts to 100 megawatts, the size and rating of the relays vary considerably. Study of relays is now being included in the engineering curriculum. M/S SCR Elektroniks have developed demonstration units for different types of relays such as under protection/over protection relay, temperature protection relay, motor protection relays, AC/DC relays and contactors keeping the engineering curriculum in view.