How to measure the quality of thyristors using the pin discrimination method for thyristors

How to measure the quality of thyristors using the pin discrimination method for thyristors

Thyristor, also known as silicon controlled rectifier (SCR), is a high-power semiconductor device composed of three PN structures. In terms of performance, thyristors not only have unidirectional conductivity, but also possess more valuable controllability than silicon rectifier components, with only two states: on and off.

The method of using a thyristor with three poles is very simple. According to the principle of P-N junction, simply measure the resistance value between the three poles with a multimeter. The discrimination of thyristor pins can be done using the following methods:

1. First, use a multimeter R * 1K to measure the resistance between the three pins. The two pins with lower resistance are the control electrode and cathode, and the remaining pin is the anode.

2. Place the multimeter in the R * 10K position, pinch the anode and the other foot with your fingers, and do not let the two feet touch. Connect the black probe to the anode and the red probe to the remaining foot. If the probe swings to the right, it indicates that the red probe is connected to the cathode, and if it does not swing, it is the control electrode.

How to measure the quality of thyristors

The quality of thyristors can be measured through the following methods:

Measure the forward voltage drop and reverse resistance with a multimeter. Adjust the multimeter to the diode test mode, connect the anode and cathode of the thyristor to the positive and negative terminals of the multimeter, and measure the forward voltage drop and reverse resistance. If the forward voltage drop and reverse resistance meet the specifications, then the thyristor is normal.

Measure the resistance between the control electrode and the cathode with a multimeter. Adjust the multimeter to the resistance test mode, connect the control pole and cathode of the thyristor to the positive and negative poles of the multimeter, and measure the resistance between the control pole and cathode. If the resistance value is within the specification range, the thyristor is normal.

Observe the conduction and cutoff states of the thyristor using an oscilloscope. Connect the anode and cathode of the thyristor to the positive and negative terminals of the power supply, and connect the control electrode to the signal source. Use an oscilloscope to observe the conduction and cutoff states of the thyristor. If the thyristor can conduct and cut off normally, then the thyristor is normal.

It should be noted that when measuring thyristors, excessive voltage and current should be avoided to avoid damaging the thyristors. At the same time, measurements should be taken according to the specific thyristor model and specification requirements.

Precautions for measuring the quality of thyristors

When measuring the quality of thyristors, the following points should be noted:

Before measurement, the model and specifications of the thyristor should be confirmed in order to select appropriate testing methods and instruments.

During measurement, excessive voltage and current should be avoided to prevent damage to the thyristor. Generally speaking, the forward voltage should not exceed half of the rated value, and the reverse voltage should not exceed the rated value.

When measuring, safety should be taken into account to avoid dangers such as electric shock and short circuit. Insulated gloves and tools should be used to ensure the correct and reliable wiring of testing instruments and power supplies.

Measurement should be carried out according to the correct steps to avoid misoperation and missed measurements. You should first check whether the testing instrument and power supply are normal, and then measure according to the testing method.

The measurement results should be compared with the specifications of the thyristor to determine its quality. If the measurement results do not meet the specifications, the thyristor may be faulty or damaged and needs to be repaired or replaced.

In short, when measuring the quality of thyristors, it should be done carefully, meticulously, and safely to ensure the accuracy and reliability of the test results.