SMT50-240

SMT50 ELECTRICAL CHARACTERISTICS The electrical characteristics of a SMT50 device are similar to that of a self-gated Triac, but the SMT50 is a two terminal device with no gate. The gate function is achieved by an internal current controlled mechanism. Like the T.V.S. diodes, the SMT50 has a standoff voltage (Vrm) which should be equal to or greater than the operating voltage of the system to be protected. At this voltage (Vrm) the current consumption of the SMT50 is negligible and will not affect the protected system. Resetting of the device to the non-conducting state is When a transient occurs, the voltage across the SMT50 will increase until the breakdown voltage (Vbr) is reached. At this point the device will operate in a similar way to a T.V.S. device and is in avalanche mode. As with the avalanche T.V.S. device, if the SMT50 is subjected The voltage of the transient will now be limited and will only increase by a few volts as the device diverts more current. As this transient current rises, a level of current through the to a surge current which is beyond its maximum rating, then the device will fail in short circuit mode, ensuring that the equipment is ultimately protected. controlled by the current flowing through the device. When the current falls below a certain value, known as the Holding Current (Ih), the device resets automatically. device is reached (Ibo) which causes the device to switch to a fully conductive state such that the voltage across the device is no...