T5070840B4AQ

Thyristors - SCRs are devices based on solid state power electronics, with three terminals. They have been used in power control applications since the 1950s. The T5070840B4AQ is a high-performance, three-terminal Thyristor/Silicon Controlled Rectifier (SCR) device. This SCR device provides superior control of AC line current in power control applications.

General Application Field

T5070840B4AQ is widely used in general power control applications for motor speed or current control. It can be used for switching and phase control in ac-dc and dc-dc converters, as well as for firing applications in programmable logic controllers (PLCs) and industrial automation. Other applications include AC motor drives, lighting and appliance control, AC and DC UPS systems, solar inverters, and renewable energy systems.

Working Principle

The T5070840B4AQ is a voltage-controlled active semiconductor device. When a voltage is applied to the gate terminals, it allows the current to flow from the anode to the cathode terminals. This, in turn, switches the device on. When the gate to anode voltage is removed, the device turns off and remains in that state until the gate voltage triggers it again. The SCR has two operation modes: latching and holding.

Latching Mode

In latching mode, the voltage applied to gate terminals is the only condition for turning the SCR on. This is known as the latching current, and it remains until the device is turned off manually by using the off command. This is the ideal mode for applications where the device needs to be turned on and off quickly and on demand.

Holding Mode

In holding mode, the gate voltage shouldn’t be removed until the current through the SCR is close to zero. This mode is suitable for applications where the SCR needs to remain on even though the voltage to the gate is removed. This type of mode is normally used for motor control or thyristor/triac firing circuits.

Conclusion

The T5070840B4AQ is a three-terminal solid state device designed for power control applications. It provides superior control of AC line current and is suitable for both latching and holding modes of operation. Its general application is for motor speed or current control, and is widely used in motor drives, AC and DC UPS systems, solar inverters, and other renewable energy systems.