TRANSISTOR POWER RATING

• Power transistors develop considerable amount of current and this current through the transistor elements themselves, as well as the internal connecting wires will generate a certain amount of heat.

• This raises the temperature of collector junction and places a limit on the allowable power dissipation P Depending on the transistor type, a junction temperature in the range of 150° to 200°C will destroy the transistor.

• Data sheets specify these junction temperature as Hence it becomes important with power transistors to bring out this heat at collector junction as quickly as possible and then conduct away from the unit as efficiency as possible.