What is the function of the two rows of ranges on the pointer multimeter?
Firstly, let's talk about the meter head of a multimeter. The resistor Ω ranks first in the range of the pointer multimeter head. The resistance value of the resistor should be viewed from right to left, and the resistance value increases as it moves to the left. The readings become denser as it moves to the left, until infinity, which is the inverted "8".
The range of the meter head is arranged after the resistor, which includes AC voltage, DC voltage range, and DC current range. The readings of these ranges are normal when viewed from left to right, and they increase as you move to the right.
Further back are the capacitor, transistor, and battery gears, which I won't go into detail about.
Next, let's talk about the dial. The most special feature on the dial is the resistance range (Ω), and the range of the Ω range is all multiples of the actual reading being measured. For example, when you read 100 on the meter, it must be 1000 ohms at 10.
The reading of DCV DC voltage, ACV AC voltage, and DCMA DC current is relatively normal. Just select a certain position and calculate according to the proportion. For example, if you measure an AC voltage of 220 and select the 500V gear, you must divide the dial into five equal parts, so the 220 position is in the middle left position.
The other gears, such as the six holes in the upper left corner, are for measuring HFE transistors, OFF is for shutting down, and C is for measuring capacitance.
Method for determining the polarity of a transistor using a digital multimeter
Connect the meter rod to the other pin, connect the black meter rod to the other two pins, measure another set of data, then connect the red meter rod to the third pin, connect the black meter rod to the other two pins, and measure another set of data. If two of the three sets of measurement data in one set are around 600 (which is the voltage drop of the PN junction), it indicates that the pin connected to the red meter rod is the base and the transistor is an NPN transistor.
For a transistor, only when the red meter rod is connected to the base and the black meter rod is connected to the other two pins, will the digital multimeter display a forward voltage drop of around 600 after the diode is turned on. Due to the widespread use of NPN type transistors, for convenience, a red meter rod should be connected to a pin to determine whether it is an NPN type transistor.
