DC voltage measurement, such as batteries, Walkman power supply. First of all, the black pen into the "com" hole, the red pen into the "V Ω". Select the knob to a range larger than the estimated value (Note: the values on the dial are the maximum range, "V-" means DC voltage gear, "V ~" means AC voltage gear, "A " is the current gear), then connect the meter pen to the power supply or battery ends; keep the contact stable. The value can be read directly from the display, if it shows "1.", it indicates that the range is too small, then you have to increase the range and then measure. If there is a "-" on the left side of the value, it indicates that the polarity of the pen is opposite to the actual power supply polarity, and the red pen is connected to the negative pole.
Measurement of DC current. First, insert the black pen into the "COM" hole. If the measurement is greater than 200mA of current, the red pen should be inserted into the "10A" jack and the knob to DC "10A" gear; if the measurement is less than 200mA of current, the red pen should be inserted into the "200mA" jack. 200mA" jack, the knob to DC 200mA within the appropriate range. After adjusting, it is ready to measure. String the multimeter into the circuit, keep it stable, you can read. If the display is "1.", then we need to increase the range; if the value of the left side of the "-", it shows that the current from the black pen into the multimeter.
AC current measurement. Measurement methods and 1 the same, but the gear should be played to the AC gear, current measurement is completed should be inserted back into the red pen "VΩ" hole, if you forget this step and directly measure the voltage, haha! Your table or power supply will be "a wisp of smoke on the clouds" - scrapped!
Pen will be inserted into the "COM" and "VΩ" hole, the knob knob to "Ω" in the required range, with the pen connected to the resistance of the two ends of the metal parts of the measurement can be contacted with your hand! Resistance, but do not touch both ends of the resistance at the same time, which will affect the accuracy of the measurement - the human body is a very high resistance but limited conductor. Readings, to keep the pen and resistance have good contact; attention to units: in the "200" gear unit is "Ω", in the "2K" to "200K" gear unit is "Ω", in the "2K" to "200K" gear unit is "Ω", in the "2K" to "200K" gear unit is "Ω". 200K" file when the unit is "KΩ", "2M" above the unit is "MΩ".
Digital multimeter can measure light-emitting diodes, rectifier diodes ...... measurement, the position of the pen with the same voltage measurement, the knob will be rotated to the " " file; with a red pen connected to the diode's positive pole, the black pen connected to the negative pole, which will show the diode's positive voltage drop. Schottky diode voltage drop is 0.2V or so, ordinary silicon rectifier (1N4000, 1N5400 series, etc.) is about 0.7V, light-emitting diode is about 1.8 ~ 2.3V. switch the pen, the display shows "1." is normal, because the reverse resistance of the diode is very large, otherwise the tube has been broken.
Pen insertion as above; the principle of the same diode. First assumed that the A foot for the base, with the black pen and the foot connected to the red pen and the other two feet were in contact with the other two feet; if the two readings are 0.7V or so, and then use the red pen to connect to the A foot, the black pen in contact with the other two feet, if they show "1", then the A foot for the base, otherwise you need to re-measurement, and this tube is a PNP tube. So how to judge the collector and emitter? Digital table can not be used like a pointer table to judge the amplitude of the pointer, then how to do? We can use the "hFE" file to judge: first gear to "hFE" file, you can see a row of small jacks next to the file, divided into PNP and NPN tube measurement. The previous tube type has been judged, the base will be inserted into the corresponding tube type "b" hole, the remaining two feet were inserted into the "c", "e" hole, at this time you can read the value, that is, -value; then fixed Then fix the base pole, the other two feet to the adjustment; compare the two readings, the reading of the larger pin position and surface "c", "e" corresponds to.
Tips: on the method can only be directly on the 9000 series of small tube measurements, if you want to measure the large tube, you can use the wiring method, that is, with a small wire will be three pins lead out. This is a lot more convenient Oh.
