How do you look at the resistance of the universal meter? Why is my test different from what the sto

To measure the resistance with a multimeter, you need to adjust the zero first, which is to hit the selected range in the ohm range, and then touch the red and black lines together, and adjust the pointer so that it points to the rightmost 0 scale. After changing the range, it should be reset to zero. The resistance value of the light-emitting diode with a multimeter seems to be undetectable, and the measurement will not be correct.

It should be the resistance gear that should be selected first to connect the two meter pens to zero, and then measure the reading.

The basic operation method of multimeter resistance measurement.

First of all, connect the watch pen, the choice of the multimeter can be a pointer or a digital display, the red watch pen is inserted into the V file, and the black watch pen is inserted at the com end to ensure that the multimeter is normal.

If you are not sure how much the resistance value is, you should first switch the range and put it at the maximum value, and then switch from a large number of ranges to a small range file, so that the instrument pointer indicates more than 1 2 at the full scale.

After selecting the appropriate magnification level, the two watch pens touch so that the pointer points to the zero position, if the pointer deviates from the zero position, the "zero" knob should be adjusted to make the pointer zero, so as to ensure the accuracy of the measurement results.

Connect the two sections of the resistor, the watch pen is connected casually, there is no positive or negative difference, and you must ensure that the contact is good.

Read out the data displayed by the multimeter, if there is no data in the multimeter, it may be that the resistor is broken, of course, there is also a possibility that the range is not enough, replace the range.

If there is no data all the time, it can only mean that the resistor is broken. If there is a data output data, pay attention to the units of the gear added.

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1. Cut off the power supply first, put the multimeter function switch in the buzzer position, and put the two meter pens of the multimeter on the two terminals to be measured. If there is a short circuit, there will be a buzzer and a small conduction voltage value will be displayed. At this point, the two test points are short-circuited.

2. Measure the line insulation with a multimeter to determine whether the line is short-circuited. For example, if the insulation value is zero (metallic ground) or very low (non-metallic ground), the phase wire grounding can be judged. If not grounded, the insulation value is high.

Re-measure the phase-to-phase insulation. If the phase-to-phase insulation is zero, it means that there is a short circuit between the two phase wires. 3. When the line is not energized, use the resistance gear (put the pointer meter in the RX10 gear, and the digital display table will be temporarily connected to the disconnection gear) and contact with the two points (or two wires) to be measured.

If the pointer table does not move, it is an open circuit, and if it is full, it is a short circuit; The number of open circuits in the digital meter remains unchanged, and if there is no sound, it is a short circuit, or zero. 4. Separate the cores at both ends of the wire and do not touch each other. Then, turn the multimeter to the upper position and attach the pen to the wire ends of the two different colors.

If the measurement is 0, it means that both wires are shorted. If it is displayed as infinite, the wire is good.

The multimeter ohmic file can measure the resistance of a conductor. Ohmic gears are denoted by " and are divided into four gears: R 1, R 10, R 100 and R 1K. Some multimeters also have R 10k gears.

In addition to the requirements that should be done before use, the following steps should be followed:

Set the selector switch to the R 100 position, and short the two watch pens to adjust the ohmic zero adjustment knob so that the watch hand points to the zero position at the right end of the resistance scale. If the pointer cannot be adjusted to zero, the battery voltage in the meter is insufficient and the battery should be replaced.

Use two gauge pens to contact the two pins of the resistor to be measured respectively. Correctly pronounce the value of the resistance indicated by the pointer and multiply it by the multiplier (100 for R 100 and 1000 for R 1k......).) is the resistance value of the resistor being measured.

In order to make the measurement more accurate, the pointer should be pointed near the center of the scale mark. If the pointer declination angle is small, switch to R 1K, and if the pointer declination angle is large, switch to R 1O or R 1. After each shift, the ohmic zero adjustment knob should be adjusted again before measuring.

The principle of multimeter resistance measurement:

The principle of multimeter resistance measurement is actually based on Ohm's law. In the multimeter, its voltage is the voltage of the battery; There are several resistance values, including the resistance we want to test, its adjustable resistance (its internal resistance is different for different gears of the multimeter), and its constant resistance. The current is calculated when our test resistance is equal to zero.

In this way, we get a formula: i=U (RG+R+R+R+R) U is the voltage of its internal battery, Rg is the resistance of the meter, R, a fixed value resistance in series with the meter, R-tune, zero-adjusted variable resistance, R-meter, the resistance to be measured. Due to the different range of resistors to be measured, the fixed value resistors used are also different, which makes it possible to divide the multimeter into several gears.

One is to affect the accuracy of the measurement results, and the other is to burn out the multimeter.

When measuring resistance with a multimeter, you need to pay attention to:

1) Select the appropriate magnification level so that the pointer is as close to the center of the scale as possible to ensure that the reading is more accurate. When measuring, the indicated value of the pointer on the scale is multiplied by the magnification, which is the resistance value of the resistor being measured.

2) Before measuring the resistance, or after changing the different magnification gears, the two meter pens should be shorted, and the zero knob should be used to adjust the zero, and the battery should be replaced when the zero position cannot be adjusted. After the measurement, the transfer switch should be dialed to the highest AC voltage or neutral gear to prevent the meter pen from short-circuiting, resulting in short-circuit discharge of the battery. At the same time, it also prevents forgetting to dial the gear to measure the voltage and burning the meter head during the next measurement.

3) Do not measure the resistance with electricity, otherwise not only will you not get the correct reading, but you may also damage the meter head.

4) When measuring the positive and negative resistance of semiconductor components with a multimeter, R*100 gear should be used, and high resistance gear should not be used to avoid damage to semiconductor components.

5) It is strictly forbidden to directly measure the internal resistance of micro-ampere meters, galvanometers, standard batteries and other instruments with the resistance of multimeters.

Multimeter to judge the good and bad resistance method:

1. Use the multimeter to select the appropriate gear.

In order to improve the measurement accuracy, the gear should be selected according to the magnitude of the nominal value of the resistance. The indicated value of the pointer should fall as far as possible in the middle of the scale (i.e., within 20% of the 80% radian from the start of the full scale) to make the measurement data more accurate. The nominal resistance value is read according to the nominal resistance.

Turn on the multimeter gear switch and adjust the multimeter to the appropriate ohmic gear according to the nominal resistance of the resistor.

2. Use a multimeter to calibrate zero.

Short the red and black watch pens and adjust the fine adjustment knob so that the multimeter pointer points to 0 before testing. When using an analog multimeter for detection, it is also necessary to perform the key step of correcting (adjusting) the meter hand to zero, by placing the multimeter behind an ohmic stop, shorting the red and black watch pens, adjusting the fine adjustment knob so that the multimeter pointer points to the 0 position, and then testing.

3. Measure and read with a multimeter.

The actual resistance value can be measured by connecting the two meter pens (regardless of positive and negative) with the pins at both ends of the resistor. When measuring, the reading is taken after the watch hand is stopped, and then multiplied by the magnification, which is the measured resistance beat standby value.

Usually, the ohmic stop of an analog multimeter is divided into five stops, and the index value of the pointer is multiplied by the gear to be the actual resistance of the resistor being measured. When observing the resistance reading of the resistor being measured, both eyes should be directly above the rolling macro multimeter (i.e., the eyes should be perpendicular to the multimeter), and if there is a curved mirror in the dial, the reading can only be taken when the pointer coincides with the image in the mirror. If the pointer is between two tick marks, in addition to reading out the resistance represented by the tick marks, you should also estimate the numerical noise between the ticks.

Summary: If the resistance value measured by the multimeter is equal to the nominal resistance value of the resistance or within the error range of the resistance, the resistance is normal; If there is a large deviation between the two, that is, the actual resistance value displayed by the multimeter exceeds the error range of the resistor, the resistance is bad; If the multimeter measures a resistance value of infinity (open circuit), zero resistance value (short circuit), or unstable, the resistance is damaged and can no longer be used.

Set the multimeter in a suitable resistance setting, and the resistance is placed separately on the insulation, so that the measuring rod can firmly touch both ends of the resistance and the resistance value can be read out. If it is within the labeled group values and within the margin of error, it is normal. When measuring, the conductors at both ends of the resistor and the metal part of the measuring rod must not touch any circuit or conductor (including the hand or the human body) to avoid interfering with the test and producing erroneous values.

If a test clamp is used, the resistor can also be paused to expand the data. Multimeter, also known as multiplex meter, multi-meter, multi-meter, etc. It is an indispensable measuring instrument for power electronics and other sectors, and its main purpose is to measure voltage, current, and resistance.

Multimeters are divided into analogue multimeters and digital multimeters according to the way they are displayed. It is a versatile, multi-range measuring instrument. Generally, multimeters can measure DC current, DC voltage, AC current, AC voltage, resistance and audio level, and some can also measure AC current, capacitance, inductance and some semiconductor parameters (such as).

1.First, check the appearance of the resistor for abnormalities, such as blackening, breakage, cracking, pin oxidation, color coding or labeling, etc. If there is such an anomaly, it is a bad resistor.

2.The multimeter should be set at the appropriate resistance level, and the resistance should be placed separately on the insulation. The two probes should be firmly in contact with both ends of the resistor and the resistance value should be read.

If it is within the labeled group values and within the margin of error, it is normal. Note: When measuring, the conductors at both ends of the resistor and the metal parts of the two probes must not touch any circuit or conductor (including the hand or the human body) to avoid interfering with the test and producing erroneous values.

If a test fixture is used, the resistor can also be paused.

Insert the black pen into the common input, the red pen into the resistor input, select the resistance range, and if it is an autoranging multimeter, select the resistor directly. The resistance gear and the on-off diode are generally connected together, when measuring the on-off buzzer, if the resistance of the tested line is less than 50 ohms, there will be a beep, when measuring the diode, the red pen is positive, the black pen is negative, and the screen shows the positive voltage drop of the diode.

A method for detecting the quality of a resistor.

Turning the multimeter to the resistor can be used to detect the quality of the resistor.

When detecting, first turn the gear knob on the multimeter to the appropriate gear according to the size of the resistor resistance. Then, short the two pens to each other and turn the "Zero" knob so that the watch hand points to the "0" position (full) of the resistance scale.

A multimeter is a way to detect the quality of a resistor.

Connect the two meter pens (regardless of positive and negative) with the two ends of the resistor respectively, and the gauge needle should be pointed at the corresponding resistance scale.

If the watch hand does not move, the indication is unstable, or the indicated value differs significantly from the value indicated on the resistor, the resistor is damaged.

When measuring resistors with resistance values of more than tens of thousands of ohms, it is important not to touch the two ends of the resistor with your hands at the same time, so as to prevent measurement errors caused by the resistance connected to the human body.

A multimeter is a way to detect the quality of a resistor.

The multimeter detects the quality of the resistance. First of all, the multimeter should be adjusted to the corresponding resistance level, and then put the red and black multimeter pen on both ends of the resistance, at this time there is a value on the multimeter to display, if the displayed value is similar to the value marked on the resistor, then the resistance is good.

One is to detect the resistance, one is not energized, check its internal resistance, and the two meter pens can directly read the voltage at both ends of the resistor! If you need to check the rheostat, you need to measure the current level! The resistance value is 220 i

The direct resistance level measurement of the ammeter pen is not as accurate as the resistance level of the voltmeter pen.

Hit the electric resistor, measure it and see the value.

You can use the ohm file to measure the resistance, if the resistance value is normal, the resistance is good.

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The resistance values measured by the multimeter and the resistance tester are different, mainly for the following reasons:1The measuring principle is different:

The multimeter uses Ohm's law to measure resistance, and the measured current is small, and the effect on the body being measured is also small. The resistance tester mostly uses the bridge method, which needs to detect the resistance by applying a certain measurement signal, and its measurement current is large, which will have a certain impact on the measured body, and the measurement results are different due to the conductive huna. 2.

The measurement method is different: the multimeter is a manual double-ended measurement, the connection is cumbersome, and the contact resistance is difficult to eliminate, which affects the measurement accuracy. The resistance tester realizes four-terminal measurement through professional junction boxes and fixtures, which can effectively reduce the contact resistance and make the measurement more accurate.

3.Different measurement range and resolution: The multimeter has a wide measurement range and resolution, which is suitable for a wide range of resistance testing.

The measurement range of the resistance tester can be more focused, the resolution is higher, and it is more conducive to testing the resistance of precision electronic components. This can also result in slightly different measurements for the same resistance. 4.

Calibration and accuracy are different: Professional resistance testers perform more rigorous calibration to ensure high measurement accuracy and accuracy. The calibration and accuracy of the multimeter are low, and the measurement error is also relatively large, which will also increase the deviation of the measurement results.

To sum up, although the multimeter can also measure resistance, compared with the professional resistance tester, there are great differences in its measurement principle, method, range, accuracy, etc., and it is difficult to achieve high measurement accuracy, so the measured resistance value is not the same.