P0904UARP Circuit Protection

Thyristors

A thyristor is a solid-state electronic device with four layers of alternating N and P-type materials. It acts as a switch, conducting when the gates receives a current trigger, and continuing to conduct until the current is reversed. Thyristors can be used as regular switch, where the gate current is a steady current or pulse, or for rectifying AC to DC.

P0904UARP Application Field and Working Principle

The P0904UARP is an overvoltage protection thyristor module designed for telecommunications, industrial and consumer applications. This can protect against power surges, and has an adjustable trip voltage level from 4.3V – 45V. The trip voltage level and circuit current can be adjusted via case-mounted external resistors. The module includes an input resistor to ensure the protection devices stay within their safe-operating area. The module turns off with a turn-off time of typically 3 – 5ms (depending on circuit characteristics).

Application Field

The P0904UARP module is designed for circuit protection for digital signature and telephone equipment, as well as industrial electronic control systems. It can also be used in consumer appliances and DVD players.

Working Principle

The module works as a voltage-controlled switch. It senses the input voltage and compares it with the adjustable trip voltage. If the input voltage exceeds the trip voltage level, the thyristor is triggered, and stays in the ON state until the current is reversed. When the current is reversed, the thyristor returns to its OFF state.

When the trips voltage level and circuit changes, the trip current rating should be adjusted accordingly, otherwise the thyristor can be over-stressed. The trip current can be adjusted internally by adjusting the input resistor.

Conclusion

The P0904UARP is a versatile and convenient overvoltage protection module for telecommunications, industrial and consumer systems. With adjustable trip levels and impulse trip, it can protect against power surges with minimal effort.