Measurement of Digital Multipurpose MOS Field Effect Transistor
1. Voltage level:
During testing or production, it can be used to measure the voltage of each pin of the device, and compare it with the normal voltage to determine whether it is damaged. It can also be used to detect the voltage stabilization value of a Zener diode with a small voltage stabilization value. The principle is as shown in the figure: R is 1K. The voltage at the power supply terminal depends on the nominal voltage stabilization value of the Zener diode, which is generally larger than the nominal voltage. Above 3V, but not more than 15V. Then use a multimeter to detect the voltage value at both ends of the D tube. This value is the actual regulated voltage value of the D tube.
2. Current gear
Insert the meter into the circuit to measure and monitor the current. If the current deviates far from the normal value (based on experience or original normal parameters), the circuit can be adjusted or repaired if necessary. You can also use the 20A range of the meter to measure the short-circuit current of the battery, that is, connect the two test leads directly to both ends of the battery. Remember that the time should not exceed 1 second! Note: This method is only applicable to dry batteries, AA, and AA rechargeable batteries. Beginners must be guided by personnel who are familiar with maintenance. Do not operate by yourself! The battery can be judged based on the short-circuit current. Performance, when the same type of battery is fully charged, the larger the short-circuit current, the better.
3. Resistance level;
One of the methods that can be used to judge the quality of resistors, diodes, and transistors. When the actual resistance value of a resistor deviates too much from the nominal value, it is damaged. For a diode and transistor, if the resistance between any two legs is not very large (above several hundred K), it can be considered that the performance has declined or has been damaged by breakdown. Note that this transistor is not resistive. This method can also be used for manifold blocks. It should be noted that the measurement of manifold blocks can only be compared with normal parameters.
4. Nowadays, the test leads of ordinary multimeters have large resistance values. Interested enthusiasts can make a pair of test leads by themselves; method: prepare about one meter of speaker wire or multi-core copper wire, and a pair of clips with insulating sleeves (red Black), a pair of banana plugs (red and black) for speaker wiring; one end of the wire is welded firmly to the clip, and the other end is connected to the banana plug accordingly; a pair of excellent test leads is ready.
