N-channel has domestic 3D01, 4D01, Nissan 3SK series. Determination of G pole (gate): use the diode file of the multimeter. If the forward and reverse voltage drop between a pin and the other two pins is greater than 2V, it will display "1", and this pin is the gate G. Then exchange the test leads to measure the remaining two feet. In the time when the pressure drop is small, the black test lead is connected to the D pole (drain), and the red test lead is connected to the S pole (source).
Voltage block:
When testing or manufacturing, 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 regulator value of the Zener diode with a small voltage regulator value. The principle is as follows: R is 1K, and the voltage of the power supply terminal depends on the nominal voltage regulator 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 voltage regulation value of the D tube.
current block
Connect the meter in series to the circuit to measure and monitor the current. If the current deviates far from the normal value (based on experience or the original normal parameters), the circuit can be adjusted or repaired if necessary. You can also measure the short-circuit current of the battery by using the 20A range of the meter, that is, connect the two test leads directly to both ends of the battery. Remember that the time should never exceed 1 second! Note: This method is only suitable for dry batteries, AA batteries, AA batteries, and AA batteries. Beginners should be guided by personnel who are familiar with maintenance, and must not be operated by themselves! The performance of the battery can be judged according to the short-circuit current. In the case of a fully charged battery of the same type, the larger the short-circuit current, the better.
electrical blocking;
One of the methods that can be used to judge the quality of resistors, diodes, and triodes. When the actual resistance value of the resistor deviates too much from the nominal value, it will be damaged. For two or three diodes, if the resistance between any two pins is not very large (a few hundred K or more), it can be considered that the performance is degraded or has been broken down and damaged. Note that this transistor is not band-impeded. This method can also be used for the integrated block. It should be noted that the measurement of the integrated block can only be compared with the normal parameters.
4. The test pens of ordinary multimeters have a large resistance value. Interested enthusiasts can make a pair of test pens by themselves; method: prepare a high-quality speaker wire or multi-core copper wire of about one meter, 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 on the clip, and the other end is connected to the banana plug accordingly; a pair of excellent test leads is done.
Capacitance test
Before connecting the capacitor under test, note that it takes time to reset to zero each time the range is changed, and the presence of drift readings will not affect the test accuracy.
⒈Set the function switch to the capacitance range C(F)
⒉Insert the capacitor into the capacitor test seat
Notice:
⒈ The instrument itself has set up protection for the capacitor block, so it is not necessary to consider the polarity and capacitor charge and discharge during the capacitor test process.
⒉ When measuring capacitance, insert the capacitor into the special capacitance test seat.
3. It takes a certain amount of time to stabilize the reading when measuring large capacitance.
⒋ Unit conversion of capacitor: 1μF=106pFlμF=103nF
Continuity test
⒈Insert the black test lead into the COM jack and the red test lead into the V/Ω jack (the polarity of the red test lead is "+"), set the function switch to the "what" block, and connect the test lead to the diode to be tested, the reading is that the diode is positive Approximate value of the pressure drop.
⒉ Connect the test leads to both ends of the line to be tested. If the resistance between the two ends is lower than about 70Ω, the built-in buzzer will sound.
