subject: The Use and Maintenance of Digital Multimeter [print this page] The Use and Maintenance of Digital Multimeter
Firstly, turn on the power of digital multimeter and select the test object such as voltage, current, resistance or other object. Secondly, determine the range, when we are unsure the range, we can set the range to maximum, then gradually reduce the maximum range. Before testing, we should check the meter pen whether in the correct hole. When we toggle the range switch, the force should be appropriate, avoiding the damage to metal switch. After testing, rotary switch should be in the high voltage profile.
Some explanations during the testing of digital multimeters:
(1) For the high impedance profile, the test results of resistance is different from the test results of pointer table. The slightly difference is due to the test conditions.
(2) When testing the physical quantity which is related to the polarity, whose polarity should be corresponded to the meter pen. That is to say when not display the polarity, the point of the red meter pen shows potential is in high-end or the side which is the current into. When the polarity shows"-", so the point of the red meter pen is in low-end potential or the side which is the current out.
(3) Resistance profile and diode profile are different from the pointer meter pen. When the pointer meter pen testing the resistance, the red pen and black pen are opposite to the polarity, that is to say black stands positive electrode, red stands negative electrode. However, the polarity of digital multimeter is the same with test source. Red pen stands positive electrode, black pen stands negative electrode. These are the same with voltage and current. It will not be confused. So it is superior than the pointer meter.
(4) When we don't know the polarity or don't know the pin order of the transistor, we can identify and certain every polarity of the transistor by times for foot using the hfe profile of transistor.
(5) Calibration
Digital multimeter should be calibrated regularly. When we are calibrating it, we should choose a similar one or a higher accuracy digital meter. The calibrated order as following: first, DC profile; second, AC profile; third, capacitance profile.
General, digital multimeter uses a 9V laminated battery, often use for a few months. Recommend you to buy a 9V rechargeable battery to have a replacement. So it can save your money.
If you are interested in digital multimeters, you might want to choose a cheap and high quality one, so you can consider to buy one on youroscilloscope.com.
