Notes on the use of multimeters
(1) Before using the multimeter, it should be "mechanically adjusted to zero", i.e., when there is no measured quantity of electricity, make the multimeter pointer point at the position of zero voltage or zero current.
(2) In the process of using the multimeter, you can't touch the metal part of the pen with your hand, so as to ensure the accuracy of the measurement on the one hand, and ensure personal safety on the other hand.
(3) When measuring a certain amount of electricity, you can't change the gear at the same time of measurement, especially when measuring high voltage or high current. Otherwise, it will destroy the multimeter. If you need to change gears, you should disconnect the meter pen first and change gears before measuring.
(4) When the multimeter is in use, it must be placed horizontally to avoid errors. At the same time, it should also be noted to avoid the influence of external magnetic field on the multimeter.
(5) After the multimeter is used, the changeover switch should be placed in the maximum stop of AC voltage. If it is not used for a long time, the battery inside the multimeter should be taken out to avoid the battery corroding other devices inside the meter.
The use of ohmmeter
I. Choose the appropriate multiplier. In the ohmmeter resistance measurement, should choose the appropriate multiplier, so that the pointer indicates in the neighborhood of the median value. It is best not to use the left third of the scale, this part of the scale is very poor intensive.
Second, to zero before use.
Third, can not be charged measurement.
Fourth, the measured resistance can not have parallel branches.
Fifth, the measurement of transistors, electrolytic capacitors and other polar components of the equivalent resistance, you must pay attention to the polarity of the two pens.
Sixth, with a multimeter with different multiplication of the ohm block to measure the equivalent resistance of non-linear components, the measured resistance value is not the same. This is due to the median resistance and fullness current of each gear caused by the different mechanical meter, generally the smaller the multiplier, the smaller the measured resistance.
When measuring DC with multimeter
Zero the meter mechanically.
Second, select the appropriate range gear.
When measuring current, the multimeter should be connected in series in the circuit to be measured, because only the series connection can make the current flowing through the ammeter be the same as the current of the branch circuit to be measured. Measurement, should be disconnected from the measured branch circuit, the multimeter red and black pens connected in series between the two points of the quilt disconnected. Special attention should be paid to the current transcription can be connected in parallel in the quilt measurement circuit, it is very dangerous to do so, very easy to make the multimeter burned.
Fourth, pay attention to the measured power polarity.
Fifth, the correct use of scale and read.
Sixth, elected to take the DC current 2.5A block, the multimeter red pen should be inserted in the 2.5A measurement jack, range switch can be placed on the DC current block of any range.
If the DC current measured by the quilt is greater than 2.5A, the 2.5A block can be extended to 5A block. Method is very simple, the user can be in the "2.5A" jack and the black pen jack access to a 0.24 ohm resistor, so that the block has become a 5A current block. Access to the 0.24A resistor should be selected with more than 2W wirewound resistor, if the power is too small will make it burn.
