Multimeters' special functions and applications
Multimeter with more features, easy to use has become an essential tool in the hands of electrical and electronic engineers, but if you want to give full play to its role, fast and accurate to get accurate data. Then we also need to know more about some of the qualities of the multimeter:
1. digital multimeter must be better than analogue multimeter?
Solution: Digital multimeters are rapidly being used for their safety qualities such as high accuracy and sensitivity, fast measurement speed, many functions, small size, high input impedance, easy observation and powerful communication functions. There is a trend to replace the analogue pointer meter.
But in some occasions, such as electromagnetic interference is very strong occasions with a digital multimeter test data may deviate greatly, because the digital multimeter input impedance is very high, very susceptible to the influence of inductive potential.
2. in the maintenance, through the elimination method suspected that the diode or transistor in the circuit may be damaged. But with a digital meter diode file measured its conduction voltage of about 0.6V, reverse infinity. No problem, and then check the circuit is no fault found, why?
Solution: Most of the digital meter diode file issued by the test voltage of about 3 ~ 4.5V, if the test transistor has a slight leakage or characteristic curve has become bad, in such a low voltage can not be seen. At this time we must use analogue table × 10K resistance file, the file issued by the test voltage of 10V or 15V, in the test voltage will be found to be suspected of transistor leakage in the reverse direction. Similarly in the measurement of some very low voltage resistance of precision sensitive components, the use of analogue meters are very easy to damage the sensitive components. This time to use a digital meter to measure. 3.
3. with a multimeter to measure the high voltage probe attenuation of the voltage value, the results found that the DCV test is more accurate, but the ACV error is very large. This is true even with a highly accurate multimeter, why?
Solution: The vast majority of multimeters are connected in parallel to measure voltage, and the voltmeter itself is equivalent to a load for the entire test circuit, which is the input impedance. The larger the load impedance, the smaller the impact on the circuit under test, and the more accurate the test. But nothing can be perfect, high impedance should be sacrificed to test the bandwidth. Currently on the market in the frequency response of about 100KHz multimeter input impedance of 1.1M or so, so in the test of high-resistance load voltage at the end of 2 will have a great impact, such as high-voltage probe itself is very high resistance. This time you have to use a multimeter with high internal resistance.
4. I want to measure voltage and current, motor winding impedance, etc., as well as RPM in a practical test, is there a multimeter that can perform that function?
Solution: ESCORT (Fortune)-172 handheld digital multimeter can meet your above requirements, at the same time it meets the safety standards of the International Electro-Electronic Commission IEC1010-1 CATII 1000V, CATIII 600V standards, so you can rest assured that even in the three types of environments you can be used without worrying about safety issues.
5. Is there a very cheap and reliable and stable performance of the digital multimeter?
(Solution: There is such a good thing under the sky trouble you also tell me a :). But relatively speaking, Taiwan ESCORT (Fortune) production of digital multimeter cost-effective.
