Precautions for using MOS tubes — SUNMATE

Precautions for using MOS tubes

1) In order to safely use field-effect transistors, the limit values of the dissipated power, maximum drain source voltage, maximum gate source voltage, and maximum current of the transistor cannot be exceeded in the design of the circuit.

2) When using various types of field-effect transistors, it is necessary to strictly follow the required bias connection circuit and comply with the polarity of field-effect transistor bias. If there is a PN junction between the source and drain of the junction field-effect transistor gate, the N-channel transistor gate cannot be positively biased; The P-channel gate cannot be subjected to negative bias, and so on.

3) Due to the extremely high input impedance of MOS field-effect transistors, it is necessary to short-circuit the leads during transportation and storage. Metal shielding packaging should be used to prevent external induced potential from breaking down the gate. It is particularly important to note that MOS field-effect transistors cannot be placed in plastic boxes. It is best to store them in a metal box and also pay attention to the moisture resistance of the tubes.

4) In order to prevent gate induced breakdown of field-effect transistors, it is required that all testing instruments, workbenches, soldering irons, and the circuit itself must have good grounding; When welding the pins, first weld the source electrode; Before connecting to the circuit, all lead ends of the tube should be kept in a short circuit state with each other, and the short circuit material should only be removed after welding is completed; When removing the tube from the component rack, it should be ensured that the human body is grounded in an appropriate way, such as using a grounding ring; Of course, if advanced gas-thermal electric soldering irons can be used, welding field-effect transistors is relatively convenient and ensures safety; When the power is not turned off, it is absolutely not allowed to insert the tube into the circuit or remove it from the circuit. The above safety measures must be taken with caution when using field-effect transistors.

5) When installing a field-effect transistor, pay attention to avoiding the installation position as close as possible to the heating element; In order to prevent pipe vibration, it is necessary to tighten the pipe shell; When bending the pin lead, it should be carried out at a position 5mm larger than the root size to prevent bending the pin and causing air leakage.

For power type field-effect transistors, it is necessary to have good heat dissipation conditions. Because power type field-effect transistors are used under high load conditions, it is necessary to design sufficient heat sinks to ensure that the shell temperature does not exceed the rated value, so that the device can work stably and reliably for a long time.

In short, to ensure the safe use of field-effect transistors, there are various precautions to be taken and various safety measures to be taken. Professional and technical personnel, especially electronic enthusiasts, should take practical and feasible measures based on their actual situation to safely and effectively use field-effect transistors.