Common damages and other issues in the use of MOS/field-effect transistors

There may be several reasons for the damage:

1. Lack of protection circuit. Generally speaking, a protection circuit should be appropriately set up in the circuit to absorb transient high voltage and surge voltage in the circuit and protect key components

2. The parameter selection is unreasonable. There should be some margin for the voltage and current of the thyristor to ensure normal use. If the parameter selection is overly conservative, it is essentially equivalent to operating under overload conditions, which can easily lead to damage over time

3. The components have not been carefully screened or aged, or high-quality components have not been selected at all. The probability of damage during use is certainly high       

4. Accidental results. The motherboard itself has a certain probability of being damaged

When encountering similar issues, a test can be conducted on the materials:

Question 1: How to use a digital multimeter to detect whether a field-effect transistor (FET) is good or bad?

Question 2: How to use a digital multimeter to identify the D, S, and G terminals of a field-effect transistor (FET)?

Question 3: How to use a digital multimeter to determine the type of field-effect transistor (whether it is N-channel or P-channel)? The detection method is as follows:

Column: N-channel

1. Connect the red probe to the first pin, and connect the black probe to the other two pins respectively. At this point, there is no reading on the multimeter, which means there is no response. Then the red probe is connected to the G terminal

2. Connect the red probe to the second pin and the black probe to the third pin, and there is a reading. That means they are connected. Keep the red probe still. Connect the black probe to the G terminal (which has already been tested). Then connect the black probe to the third pin. It is found to be disconnected. (This indicates that the tube is 99% good). (The second and third pins are connected because they were charged in the first step. Later, they became disconnected because the red probe was connected to the second pin and the black probe was connected to the first pin, discharging them.)

3. Connect the red probe to the third pin and the black probe to the second pin. If there is a reading, then the red probe is connected to the S pole and the black probe is connected to the D pole