Two,bi-directional thyristor
Two,bi-directional thyristor
Bidirectional thyristor is a new semiconductor device developed on the basis of unidirectional thyristor.Bidirectional thyristor is a three-terminal semiconductor device made of NPNPN five-layer semiconductor material.The three electrodes are the main electrode T1,the main electrode T2 and the control electrode G.The two way thyristor has a bidirectional conductivity between the anode and the cathode,and the internal circuit can be equivalent to a composite tube consisting of two unidirectional thyristors.
The pointer type multimeter detects the bidirectional thyristor as follows.
First determine the main electrode T,the control pole G and the main electrode T,the distance between the closer,and its positive and negative resistance are small.When measuring the resistance between G,T and two feet with the multimeter RX12,the deflection amplitude of the gauge needle is relatively large,and the positive and negative resistance between G ~ T2 and T ~ T are infinite.This indicates that if a foot and other two feet are detected, it is possible to determine that the foot is a T2 pole. A bidirectional thyristor T2 with a radiating plate is often communicated with a heat sink. After dimension 2 determines the T2 pole, suppose that one foot of the remaining two feet is work,pole,and the other foot is I get G pole,and the black pen is assumed to be the T pole,the red stylus is connected to the T2 pole,and in the case of the black stylus keeps open W and T,the T 2 pole is instantaneously shorted with the hypothetical G pole ( negative trigger signal is added to the G pole ) ),the pointer of the multimeter is deflected to the right,indicating that the pipe has been turned on,the direction of the jade and the direction of TT are turned on,and the two poles of the above hypothesis are correct.If the multimeter is not indicated,the value of the resistance t is still infinite,indicating that the pipe is not turned on, and if the error is assumed,the bipolar hypothesis can be changed,connect the stylus and retest.
The red stylus is connected to the T1 pole,the black stylus is connected to the T2 pole, and then the T2 pole and the G pole are instantaneously shorted ( plus the positive trigger signal to the G pole ),the resistance value is still small,which proves that the tube is turned on again and the conducting direction is T2T1.Piece.If you measure it according to which assumption,you can't make the bi-directional gate tube turn on,which proves that the pipe is damaged.
Once the thyristor is turned on,the control pole will lose control.When the operating current of the thyristor is less than the maintenance current,the thyristor can be cut off. The working state of the turn-off thyristor is different from them.The control pole not only controls the conduction current,but also can trigger the pipe to be turned on by the cutoff,it can also control the tube from conduction to cutoff,highlighting the characteristics of turn-off,so it is called turn-off thyristor.Mainly used for inverter, DC interrupter and other places that need to be forced off,you can simplify the main circuit.