Understand avometer deep
Understand avometer deepAvometer with the function much, use easily simply already became electronic electrician the indispensable tool in Cheng division hand, but if want to develop its action adequately, get accurate data well and truly quickly. Then we still need to understand avometer deep more a few idiosyncratic:
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1.It is good that digital avometer compares imitate avometer certainly? Solution: Digital avometer is spent definitely with its essence and sensitivity is tall, measure speed fast, function much, bulk impedance of small, input the fine quality such as tall, facilitating observation and strong communication function, be able to apply quickly. Have the trend that replaces imitate finger watch. But in certain circumstance, the data that the circumstance with electromagnetism very for instance strong interference checks with digital avometer may error is very big, because impedance of digital avometer input is very tall, suffer the influence of inductive electromotive force extremely easily.
2.In maintenance, passing a suspicion that check a law may be the diode in circuit or dynatron attaint. But with digital watch diode archives measures his to guide electrify pressing makes an appointment with 0.6V, retrorse and boundless. Without the problem, reexamination circuit also does not have breakdown to discover, why? Solution: Most number expresses the test voltage that diode archives gives out to be 3 ～ 4.5V about, if the transistor of the test has slight leakage of electricity or characteristic curve already addle, cannot showing below such low voltage. Be about to express ×10K resistor archives with imitate at that time, the test voltage that this archives gives out is 10V or 15V, can discover below this test voltage the transistor that is suspected is to have leakage of electricity reversely. When measuring resistor of sensing element of nicety of certain compression low-down with manage, use imitate expresses sensing element of extremely easy attaint. Be about to use digital watch to measure at that time.
3.Measure the voltage value after high-pressured explore marvellous attenuation with some avometer, the result discovers DCV test is more accurate, but ACV error is very big. Although use essence of life to spend very tall avometer definitely,also be such, be because of,He Yuan? Solution: The avometer of absolutely large number uses shunt-wound means to measure voltage, to whole test circuit character volmeter itself is one load to input impedance namely with respect to equivalent. Impact of pairs of this laden impedance is bigger loop that be measured is less, the test is more accurate also. But everything cannot perfect, impedance is tall be about to sacrifice the frequency of the test is wide. The avometer that at present noise of the frequency on market controls in 100KHz inputs impedance to be 1.1M left and right sides, checking tall block load so can affect when the voltage of 2 end very big, cost of block of high-pressured explore marvellous itself is very for instance high. At that time you are about to choose the avometer of tall internal resistance, for instance ESCORT (riches and honour) the input impedance that is as high as 10000Ω is offerred when avometer of 170/172/176/178/179 hand-held number checks ACV, can avoid this problem so.
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