How to identify and detect bidirectional thyristors?

Last Update Time: 2018-12-18 15:02:24

 (1) Identification of bi-directional thyristor pins

The pin arrangement of the unidirectional thyristors of different public and common production is usually inconsistent, most of which are the down of the electrode pins and the sequence of T2, G, and Ti in the order of the character on the left to right side.

(2). Detection of bi-directional thyristor by multimeter.

1)First use RX1 or RX10 to check the resistance value between the two poles. If the positive and negative measurement fingers do not move, it may be T2, T) or T2 or G pole. If the values of the positive and reverse measurements are tens to hundreds of Europe, there must be a larger one, and the one by one red pens is connected to the gate G, the black pen is the main electrode T1, and the rest is the main electrode T2.

When the digital multimeter is detected, the digital multimeter is dialed to the diode bar, the red pen is fixed on one pin arbitrarily, and the other two pins are in contact with the black pen. If in the two test, one display value is less than 1V, the other shows the overflow symbol "OL" or "1" (depending on the different digital multimeter), indicating that the red form pin is the main electrode T2.

If the red pen is fixed to one pin, the black pen holds the second pin when the value is 0.2~0.6V black and third pins display the overflow symbol "OL." or "1", and the red form pin is connected to the second pins of the black pen. The value of the display is fixed to 0.2~0.6V, in which the red pen is connected to the pin. It is the main electrode T2, the second pin is the gate G, and the third pin is the main electrode T1.

2)Judgment is good and bad.

The positive and reverse resistance values between the T1 and the T, between the T2 and the G, should be close to infinity. If the measured resistance values are very small, the measured two-way thyristor electrode has been short circuited; the positive and reverse resistance values between T and G should be tens to one hundred ohm if the same method is used to measure the resistance value between T and G. The measured positive and negative resistance values are very large or even infinitely large, indicating that the inside of the tested tube has been damaged by circuit breakage.

3) Detection of trigger ability.

Use the multimeter RX1 or RX10k2 to block (the 10kQ block is used in high power, and the battery voltage in the meter is high). The specific methods are as follows:

G has a positive trigger signal. The multimeter selects RX1 gear, the red pen is connected to the T pole, the black pen is connected to the T2 pole, and then the T2 pole is short circuited with the G pole. At this time, the G is added to the positive trigger signal, the needle is swinging to the right, indicating that the tube has been guided and the direction of the conduction is T2 T1. Then the G pole is disconnected. If the resistance value remains unchanged, it is indicated that the bidirectional thyristor can be maintained normally in the direction of T2 to T after triggered Conduction state. G plus negative trigger signal. Still use RX1 or RX10K2 block measurements.

First, the black pen is connected to the T pole, and the red pen is connected with the T2 pole, and the resistance value is infinite. Then the T2 and G short circuit. To G plus a negative polarity trigger signal at this time the multimeter pointer should swing to the right, indicating that the measured two-way gate tube has been turned on, the conduction direction is T. T2. Then the G pole is removed. If the resistance value remains the same, it indicates that the thyristor can still maintain the on-state after triggering. In the above measurement, if the G pole plus the trigger voltage ( G and T2 short connection ), the bidirectional thyristor can not be turned on or in the G pole to remove the trigger voltage ( G off ) can not be continue to maintain the on-state, that its performance is poor or has been damaged. But the test should be noted that the battery inside the multimeter should not be less than 1.5V, to provide enough test current, so as to meet the thyristor conduction requirements, the test results are accurate and reliable, and the misjudgment can be prevented.

 

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