Resistance measurement using a multimeter: the basics
(1) Familiar with the meaning of each symbol on the dial and the main function of each knob and selector switch.
(2) Carry out mechanical zero adjustment.
(3) According to the type and size to be measured, select the gear and range of the transfer switch, and find out the corresponding scale line.
(4) Select the position of the test lead jack.
(5) Measuring voltage: When measuring voltage (or current), choose a good range. If you use a small range to measure a large voltage, there will be a danger of burning the meter; if you use a large range to measure a small voltage, the pointer deflection is too small. Unable to read. The selection of the range should try to make the pointer deflect to about 2/3 of the full scale.
(6) Current measurement: When measuring DC current, set one switch of the multimeter to the DC current gear, and the other switch to the appropriate range from 50uA to 500mA. The range selection and reading method of the current is the same as that of the voltage. When measuring, the circuit must be disconnected first, and then the multimeter is connected in series to the circuit under test according to the direction of the current from "+" to "-", that is, the current flows in from the red test lead and flows out from the black test lead.
(7) Measuring resistance: When measuring resistance with a multimeter, the following methods should be followed: a. Select a suitable magnification gear. b ohm zeroing. Before measuring the resistance, the two test leads should be short-circuited, and the "ohm (electrical) zero adjustment knob" should be adjusted at the same time so that the pointer just points to the zero position on the right side of the ohm scale.
If the pointer cannot be adjusted to the zero position, it means that the battery voltage is insufficient or there is a problem inside the meter. And every time the magnification gear is changed, the ohm zero adjustment must be performed again to ensure accurate measurement. c reading: the reading of the meter multiplied by the magnification is the resistance value of the measured resistance.
