BT139B-800G,118

Thyristors - TRIACs

A thyristor is a type of switching element with three layers of alternating P and N-type semiconductors. A TRIAC (triode for alternating current) is a type of thyristor, basically a three terminal AC switch. The BT139B-800G is an example of a TRIAC manufactured by ST Microelectronics.

Applications

The BT139B-800G is a fast TRIAC, suitable for use in a variety of applications. It is commonly used in household appliances and motor control circuits due to its switching speed. It can also be used in power control for lamps, motors, and heating elements. Furthermore, the BT139B-800G is ideal for applications such as AC power control, light dimming, temperature control and inrush current limiting.

Working Principle

The BT139B-800G is a three layer semiconductor device, designed to act as a switch. It has three pins, called the MT1, MT2, and Gate. MT1 and MT2 represent the anode and cathode terminals, respectively, whilst the Gate terminal is referred to as the control terminal. The function of the BT139B-800G is to conduct current when a small gate current is applied. This gate current turns on the thyristor, which remains in the on-state until the gate current is removed.

When the gate current is removed, the TRIAC returns to the off state. Different signals applied to the gate terminal can control the time for which the TRIAC remains in the on-state, allowing for AC power to be regulated. The BT139B-800G can be used for controlling the current in a circuit, and can be used to provide zero voltage switching.

Conclusion

The BT139B-800G is a type of thyristor known as a TRIAC. It is designed with three layers of P and N-type semiconductors, and has three terminals. It is used in a variety of applications, including motor control and power control in domestic appliances. The BT139B-800G works by conducting current when a small gate current is applied. Different signals can be applied to the gate terminal to control the on-state duration of the TRIAC, and this in turn allows for AC power to be regulated within a circuit.