Model Multimeter Multimeter principle

Bazhou Kang Xian Zhuang power plant equipment capable multimeter, also known as multiplexing table, keyword multimeter, with three tables, table fan, is the power electronics, and other sectors essential measurement instruments, generally measuring voltage, current, and resistance is the main purpose. Press display multimeter pointer multimeter and digital multimeter divided. Is a versatile, multi-range of measuring instruments, general multimeter to measure DC current, DC voltage, AC current, AC voltage, resistance, and audio level is equal, and some can also measure AC current, capacitance, inductance and semiconductors Some parameters (e.g. β) and the like. Multimeter is the basic tool in the field of electronic test, it is also a widely used test equipment. Multimeter known multimeter, with three tables (A, V, Ω that is current, voltage, resistance with three), multiplex table, multimeter, multimeter into multimeter and digital multimeter, oscilloscope function there is a belt oscilloscope multimeter, is a keywords versatile, multi-range of measuring instruments. General multimeter to measure DC current, DC voltage, AC voltage, resistance, and audio level is equal, and some can also measure AC current, keyword, capacitance, inductance, temperature and semiconductors (diodes, transistors) are some of the parameters. DMM has become the mainstream, it has replaced analogue instruments. Compared with the analog meter, high sensitivity digital instruments keywords, high precision, clear display, overload, easy to carry, use more convenient and simple. Keywords multimeter meter is sensitive galvanometer. The head of the table printed on the dial has a variety of symbols, tick marks, and values. A sign indicates a V-Ω meter can only measure current, voltage and resistance multimeter. Dial scale printed on multiple lines, the row marked "Ω" is the resistance tick, the right end is zero, left to ∞, scale value distribution is uneven. The symbol "-" or "DC" indicates DC, "-" or "AC" indicates AC, the "~" indicates AC and DC common tick. Digital tick next few lines are different stalls and selector switch corresponding scale value. Head table also has a mechanical zero adjustment knob keyword to correct the pointer in the left zero. The basic principle is to use a multimeter sensitive magnetic DC ammeter (microammeter) do header. When a small current through the meter, there will be a current indication. However, the header can not pass high current, therefore, must be carried out in parallel with the series number of shunt resistor or down in the head of the table, thereby measure the circuit current, voltage and resistance. 4 measuring process design principles of digital multimeter will be measured by the switching circuit into a DC voltage signal, and then by an analog / digital (A / D) converter converts the voltage analog to digital, and then by electronic counter, and finally the measurement The results are displayed directly with a digital display. Multimeter to measure voltage, current and resistance function is implemented through the switching circuit section, and current, resistance measurements are based on the measured voltages, that is an extension of the digital multimeter on the basis of the digital DC voltmeter made. Digital DC voltmeter A / D converter changes continuously over time into a digital analog voltage amount, and then by electronic digital counter counts the measurement results obtained, and then decoded and displayed by the circuit measurement results are displayed. Logic control circuit controls the coordination of the circuit, keywords in the role of the clock in order to complete the measurement process. 5 common types of digital multimeter is the most commonly used as a digital instrument. Its main features are high accuracy, the main indicators of the digital multimeter display digits and display characteristics of the former characterization instrument "sensitivity", that small voltage "identification" capability; the latter reflects the measure of "accuracy", namely measurements and the true value of the degree of consistency. No necessary link between the two, and therefore can not be confused, it may not be the resolution (or resolution) mistake is similar accuracy depends on the meter internal A / D converter, the converter function was integrated error and quantization error. From the measurement point of view, the resolution is a "virtual" index (independent of measurement error), accuracy is the "real" index (which determines the measurement error was size). Keywords Therefore, any increase in display digits to improve meter resolution obtained solution is not achieved. Keywords measuring range multifunction digital multimeter, which corresponds to a different function were enough to get the maximum and minimum measurements. Keywords digital multimeter measurement rate for the number of measurements per second measured power is called measurement rate, the unit is "times / s". It mainly depends on A / D converter conversion rate. Some handheld digital multimeter measuring period representing the measured speed. Complete a required time measurement process called measurement period. Measurement accuracy rate index there is a contradiction, is usually higher accuracy, keyword digital multimeter digital multimeter classification according to the classification scale conversion can be divided into three types: manual ranging (MAN RANGZ), auto range (AUTO RANGZ), automatic / manual range (AUTO / MAN RANGZ). Depending on the function, purpose and price, digital multimeter can be divided into nine categories: low-end digital multimeter (also known as universal digital multimeter), mid-range digital multimeter, medium / high-end digital multimeter, digital / analog hybrid instruments, digital / Rendering dual display of meter, multimeter DMM (digital multimeter, digital storage oscilloscopes and other kinetic rolled into one). Keywords digital multimeter test function digital multimeter can not measure DC voltage (DCV), AC voltage (ACV), direct current (DCA), alternating current (ACA), resistance (Ω), the diode forward voltage drop (VF), transistor emitter current amplification factor (hrg), also measured capacitance (C), conductance (ns), temperature (T), frequency (f), and an increase in line to check-off stall buzzer (BZ ), low power method to measure the resistance profile (L0Ω). Some instrument also has an inductance files, signal files, AC / DC automatic conversion, automatic conversion range capacitance profile function. Digital multimeter number increased most innovative and practical following test functions: Reading Hold (HOLD), logic test (LOGIC), True RMS (TRMS), relative value measurement (RELΔ), automatic shutdown (AUTO OFF POWER) and the like. 9 Tel: 13373160272 QQ: 1471838096 Website: www.deligongju.com