The use of the ohm gear of the digital multimeter
(1) Select the appropriate magnification. When measuring resistance with an ohmmeter, an appropriate magnification should be selected so that the pointer indicates near the median value. It is best not to use the left third of the scale, which is poorly dense.
(2) Zero adjustment before use.
(3) Do not measure with electricity.
(4) The resistance under test cannot have a parallel branch.
(5) When measuring the equivalent resistance of polar components such as transistors and electrolytic capacitors, you must pay attention to the polarities of the two pens.
(6) When measuring the equivalent resistance of the nonlinear element with the ohm stop of different magnifications of the multimeter, the measured resistance values are not the same. This is because the median resistance and full-scale current of each gear are different. In a mechanical watch, the smaller the magnification, the smaller the measured resistance.
When a multimeter measures DC
(1) Perform mechanical zero adjustment.
(2) Select the appropriate range gear.
(3) When making the multimeter current block to measure the current, the multimeter should be connected in series in the quilt measuring circuit, because only the series connection can make the current flowing through the ammeter be the same as the current of the branch under test. When measuring, the branch under test should be disconnected, and the red and black test leads of the multimeter should be connected in series between the two points where the quilt is disconnected. Special attention should be paid to the fact that the current copy can be connected to the quilt test circuit in parallel. This is very dangerous, and it is very easy to burn the multimeter.
(4) Pay attention to the polarity of the measured electricity.
(5) Correct use of scale and reading.
(6) When the 2.5A block of DC current is selected, the red test lead of the multimeter should be inserted into the 2.5A measurement jack, and the range switch can be placed on any range of the DC current block.
(7) If the DC current measured by the quilt is greater than 2.5A, the 2.5A gear can be extended to 5A gear. The method is very simple, the user can connect a 0.24 ohm resistor between the "2.5A" jack and the black test pen jack, so that the gear becomes a 5A current gear. The connected 0.24A resistor should use a wire-wound resistor of more than 2W, if the power is too small, it will burn out.
