Multimeter resistance measurement diagram and precautions

Use and precautions of resistance gear turn the multimeter pointer to the resistance gear shown in the box below , The black pen is inserted in COM hole , The red pen is inserted in V hole , Then measure the resistance value of the measured resistance .

Precautions for resistance measurement

(1) If the measured resistance value exceeds the maximum value of the selected range , Overrange... Will be displayed “1”, A higher range should be selected , For greater than 1 MΩ Or higher resistance , It will take a few seconds for the reading to stabilize , This is normal for high resistance readings .

(2) When there is no input , Such as open circuit , Is shown as “1”.

(3) When checking the internal line impedance , Ensure that all power supplies of the tested line are powered off , All capacitors discharge .

(4)200MΩ There are about four words in the short circuit , When measuring, subtract... From the reading , If measured l00MΩ Resistance time , Is shown as 101.0, The fourth word should be subtracted .

(5) The resistance gear can be used to roughly detect the quality of the capacitance , Connect the red probe to the positive pole of the capacitor , The black probe is connected to the negative pole of the capacitor , The reference power supply of the multimeter will charge the capacitor through the reference resistance , Under normal conditions, the charging voltage displayed by the multimeter will gradually increase from a low value , Until overflow... Is displayed . If charging starts, overflow is displayed “1”, It means that the capacitor is open circuit ; If it is always displayed as a fixed resistance value or “000”, It indicates that the capacitor has leakage or short circuit .

(6) Check whether the circuit is on or off , The function switch should be turned to “” files , Don't use resistance gear . As long as no buzzer is heard during measurement , It can be judged that the circuit is not working .

(7) When measuring small resistance , Short circuit the two probes first , Read the self resistance of the lead wire ( It's usually 0.2～0.3 o ), To correct the measured resistance .

(8) The resistance gear has overvoltage protection function , Instantaneous MIS measurement of the voltage within the specified range will not cause damage . for example ,DT-830 The maximum allowable input voltage of resistance gear of type a digital multimeter ( DC or AC peak ) by 250 v , This is the safety value of the instrument when the resistance gear is misused to measure voltage , But do not live ( Such as batteries 、 Human body, etc ) Measure the resistance , This will cause the resistance accuracy of the multimeter to decrease , Even damage .

hFE Use and precautions of gear this gear is mainly used to measure the magnification of triode β value , Before the measurement , It must be determined that the triode is PNP Type or NPN type , At the same time, determine the polarity of each foot .

Other precautions for the use of multimeter

(1) When using a multimeter , Do not touch the metal part of the probe with your hand , On the one hand, it can ensure the accuracy of measurement , On the other hand, it can also ensure personal safety .

(2) When measuring a certain amount of electricity , Do not shift gears while measuring , Especially when measuring high voltage or large current , More attention should be paid to . otherwise , It will destroy the multimeter . If you need to shift , Disconnect the probe first , Measure after shifting . Precautions for maintenance of digital multimeter digital multimeter is a kind of precision electronic instrument , Do not change the line at will , And pay attention to the following points :

① Do not use over range .

② When the battery is not installed properly or the back cover is not tightened , Do not use a multimeter .

③ Only after the test probe is removed from the multimeter and the power is cut off , To replace batteries and fuses . Battery replacement : Be careful 9V Battery usage , If the battery needs to be replaced , Open the back cover screws , Replace with the same type of battery , When replacing the fuse , Please use the same type of fuse .

④ The multimeter has been used , The change-over switch shall be set to “OFF” block . If not used for a long time , Also take out the battery inside the multimeter , To prevent the battery from corroding other devices in the meter .

The above is an introduction to the multimeter resistance measurement diagram and precautions , If you have other usage problems , Welcome to Aetna test www.agitek.com.cn