What checks and adjustments should be made before the multimeter is used

a) Multimeter.

Before use, you should do:

1 Multimeter placed horizontally.

2 Check whether the watch hand stops at the zero position at the left end of the dial. If there is any deviation, a small screwdriver can be used.

Gently turn the gauge head.

The mechanical zero adjustment knob on the dial so that the watch hand points to zero.

3 Insert the pen into the pen jack as required.

4 Screw the selector switch to the corresponding item and range. It's ready to go.

2) After the use of the multimeter, it should be done:

1 Pull out the watch pen.

2. Screw the selector switch to the "off" mode, if there is no such mode, it should be screwed to the maximum range of AC voltage, such as the "another 1000V" mode.

3 If it is not used for a long time, the battery in the table should be removed to prevent the battery electrolyte.

Leakage and corrosion of internal circuits.

Before using the multimeter, check it for damage.

If you want to measure a higher AC voltage, also check whether there is any insulation damage in the watch pen. Ensure safety during the measurement process.

If you use an analog multimeter to measure resistance, you also need to test or zero it.

Multimeters play an indelible role in the use of electronic fields. Become a competent assistant for electronics enthusiasts. For example, the analog multimeter is also widely used in the electronic ranks.

Due to the large number of measurement items and types, the measurement is also relatively intuitive, and it is deeply loved by enthusiasts. The following takes the MF-47 multimeter as an example, and talks about several problems that should be paid attention to before measurement

1. Before use, first check whether the multimeter hand is in the zero position (the watch hand is in the zero position on the left side of the dial), otherwise it needs to be mechanically zeroed.

2. Whether the two red and black watch pen wires are connected correctly (the red watch pen is inserted into the positive pole, and the black watch pen is inserted into the negative pole), and the multimeter should be placed flat.

3. It is very important to have a clear measurement target and set the meter to the correct measurement gear! Especially when measuring voltage, the meter must not be set to the measurement current level, otherwise it will burn!

4. When measuring the voltage, the meter should be dialed to the nearest and greater than the measured voltage level, if the measured voltage is unknown, the meter should be dialed to the highest voltage for a test test, and then according to the measured voltage for precise measurement. When measuring the DC voltage, the red pen touches the positive pole to be measured, and the black pen touches the negative pole.

5. When measuring resistance, every time you change a measurement gear, you must adjust the short circuit of the watch pen to zero (zero position on the right side of the dial).

6. When measuring the current, connect the meter in series in the circuit, the red watch pen contacts the positive pole of the power supply, and the black watch pen contacts the positive pole of the electrical appliance, do not exceed the range of measuring current, otherwise, such as the watch needle is broken, etc., it is easy to damage the meter head.

7. The position of the table should be far away from the magnet to avoid the increase of errors during measurement.

(1) When using a multimeter, the first thing to do is to be tested.

DU objects (current, voltage, resistance, etc.).

The DAO toggles the transfer switch to the bit where the measurement gear needs to be measured. If there are countless hearts about the size of the measured object, you should first dial to the maximum range to test to protect the meter from damage, and then dial it to the appropriate range to measure to reduce the error in the measurement. When measuring voltage, it is necessary to prevent the transfer switch from being mistakenly turned on the current or resistance, which will damage the meter head or damage the current and resistance measurement circuit.

2) When measuring DC voltage or DC current, pay attention to the measurement polarity of the multimeter, and the positive and negative test rods of the multimeter should be connected to the positive and negative poles of the circuit, otherwise it is easy to bend the pointer.

3) When measuring the resistance between the lines, the power supply of the circuit to be tested must be cut off before the measurement. The multimeter is equipped with a zero point adjustment potentiometer, it is specially used for measuring resistance, before measuring resistance, the two test rods should be shorted, adjust the zero point potentiometer, so that the pointer is at 0, and then measure, otherwise the measured yang value will produce error.

4) When measuring 2500V AC high voltage, pay attention to personal safety, and the test rods should be placed in the corresponding correct jack of the multimeter.

5) After each measurement of the multimeter, the transfer switch should be dialed to the highest gear of AC voltage to avoid damage caused by misuse by others.

Precautions for the use of multimeters:

1. Pay attention to check the battery level in the multimeter.

2. When measuring the electric power, do not shift gears.

3. Before starting, the zeroing operation should be done.

4. During use, hands should not touch the metal part of the watch pen.

5. When in use, the universal meter must be placed horizontally.

6. After the measurement is completed, the transfer switch should be placed at the maximum block of the AC voltage.

7. When selecting the range of the multimeter, it is best to choose from low to high step by step, so as to obtain more accurate measurement data.

When using a multimeter, pay attention to testing the right parameters in the right gear.

Before using the multimeter, the multimeter should be adjusted to zero, and during use, the metal parts of the multimeter should not be touched with your hands, so as not to affect the accuracy of the multimeter detection results, and the multimeter should be placed horizontally, and the shift is not allowed during measurement, if the multimeter is not needed for a long time, the internal battery should be removed to avoid damage to the multimeter accessories due to battery corrosion.

The above is the answer to this question.

It should be noted that we need to determine the function of the electrical meter according to the content of the test.

(1) Before using the multimeter, "mechanical zeroing" should be carried out, that is, when there is no measured electricity, the multimeter pointer should be pointed at the position of zero voltage or zero current.

2) In the process of using the multimeter, do not touch the metal part of the meter pen with your hands, so that on the one hand, you can ensure the accuracy of the measurement, and on the other hand, you can also ensure personal safety.

3) When measuring a certain amount of electricity, it is not possible to shift gears at the same time as the measurement, especially when measuring high voltage or high current, more attention should be paid to it. Otherwise, the multimeter will be destroyed. If you need to change gears, you should disconnect the watch pen first, and then go to measure after changing gears.

4) When the multimeter is in use, it must be placed horizontally to avoid errors. At the same time, care should be taken to avoid the influence of external magnetic fields on the multimeter.

5) After the multimeter is used, the transfer switch should be placed in the maximum gear of AC voltage. If it is not used for a long time, the battery inside the multimeter should also be taken out to avoid the battery from corroding other devices in the meter.

(1) Before use, check whether the pointer is in the zero position, if it is not in the zero position, you should adjust the pointer zero adjuster first.

2) According to the different properties to be measured, adjust the transfer switch to the corresponding position. Special attention should be paid to the measurement of voltage, do not put the transfer switch in the current or resistance mode, otherwise it will burn out the multimeter.

3) When measuring DC current or DC voltage, the red watch rod should be inserted into the red or the jack with the + sign, and the other end should be connected to the positive pole of the measured object; The black watch rod is inserted into a black or symbolized jack with the other end connected to the negative pole of the object being measured.

4) When measuring the current, the multimeter should be connected in series in the circuit under test; When measuring voltage, the multimeter should be connected in parallel in the circuit under test.

5) When measuring voltage and current, the pointer should be in the range of 1 2 a 2 3 of the full scale, and the reading is more accurate at this time. If you do not know the size to be measured in advance, in order to avoid damaging the multimeter by choosing too small a range, you should select the maximum range of the type**, and then select the appropriate range to reduce the measurement error.

6) There are multiple scales on the scale plate of the multimeter, which represent different types of measurements. When measuring, the reading should be on the corresponding scale ruler according to the type and range selected by the transfer switch, and the magnification relationship between the selected range and the reading on the scale should be noted.

7) When measuring the resistance, the appropriate magnification position should be selected, because the scale of the resistance file is the reverse scale direction, and the scale is uneven, the more to the left, the denser the scale, the worse the measurement accuracy, so the pointer should be deflected in the sparse place of the scale, and the deflection is near the middle of the scale ruler.

8) Before measuring the resistance, the zero should be adjusted, the red and black watch rods should be shorted, and the ohmic zero knob should be turned at the same time so that the pointer points to the 0 line of the resistance scale. Every time the magnification gear is replaced, it should be zeroed before the measurement can be made. If the pointer is less than zero, the battery should be replaced.

9) When measuring the resistance, at least one end of the measured resistance is disconnected from the circuit and the power supply is cut off.

to be able to take measurements.

10) When measuring higher voltage and larger current, do not turn the switch knob live to ensure personal safety.

11) After each measurement, the transfer switch should be placed in the highest AC voltage or in neutral to avoid misuse by others and damage the multimeter.

12) If the multimeter is not used for a long time, the battery in the meter should be taken out to prevent the battery from corroding and damaging other components.

How to use a multimeter and how to use it Chapter 1.

The multimeter is a multi-functional, multi-range measuring instrument that is indispensable in electrotechnical technology. Generally, the multimeter can measure DC current, DC voltage, AC current, AC voltage, resistance and audio level, and some can also measure capacitance, inductance and some parameters of semiconductors (such as ). If it is simply distinguished according to the display mode, the multimeter can be divided into an analog multimeter and a digital multimeter.

Analog multimeter vs. digital multimeter.

Pointer multimeters and digital multimeters have their own advantages and disadvantages, and the following is a comparative analysis.

Comparison of Analog Multimeter vs. Digital Multimeter Analog vs. Digital Multimeter has its own advantages and disadvantages. An analog multimeter is an average-style meter that provides an intuitive, visual indication of readings. (Generally, the reading value is closely related to the swing angle of the pointer, so it is very intuitive).

A digital multimeter is an instantaneous dispensing style meter. It uses a sample of seconds to display the measurement results, and sometimes the results are only very similar each time, not exactly the same, which is not as convenient for reading the results as the pointer.

Analog multimeters generally do not have an amplifier inside, so the internal resistance is small.

Due to the internal op amp circuit, the internal resistance of the digital multimeter can be very large, often in 1m ohm or more. (i.e., higher sensitivity can be obtained). This allows for less impact on the circuit under test and higher measurement accuracy.

Due to the small internal resistance, the analog multimeter mostly uses discrete components to form a shunt voltage dividing circuit. Therefore, the frequency characteristics are not uniform (compared to digital), while the frequency characteristics of analogue multimeters are relatively better.

The internal structure of the pointer multimeter is simple, so the cost is low, the function is less, the maintenance is simple, and the overcurrent and overvoltage capacity is strong. The digital multimeter adopts a variety of oscillation, amplification, frequency division protection and other circuits, so it has more functions. For example, it can measure temperature, frequency (in a lower range), capacitance, inductance, signal generator, and so on.

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The installed digital multimeter has poor overload capacity due to the internal structure of the multi-purpose integrated circuit, (but now some can automatically shift, automatic protection, etc., but the use is more complicated), and it is generally not easy to repair after damage.

Digital multimeters have a low output voltage (typically no more than 1 volt). It is inconvenient to test some components with special voltage characteristics (such as thyristors, light-emitting diodes, etc.).

The output voltage of the analog multimeter is high, (there are volts, 12 volts, etc.). The current is also large (such as MF-500*1 Euro range, with a maximum of about 100 mA), which can be easily tested for thyristors, light-emitting diodes, etc.

When we have set up a small local area network, network maintenance is particularly important in order to make the network work properly. Due to the complexity of network protocols and network devices, many failures are not as simple as solving single machine failures. Locating and eliminating network faults requires not only long-term knowledge and experience accumulation, but also a series of software and hardware tools, and more importantly, your wisdom.

Therefore, every network administrator should learn more about the latest knowledge, and this article will show you how to use the Windows command line to quickly detect and troubleshoot network faults.

Run the ping command to troubleshoot the NIC.

Use the ping command to ping the local IP address, loopback address) or computer name (for example, zhddsn) to check whether the NIC and IP network protocol are properly installed.

If it can be pinged, it means that there is no problem with the network card and network protocol settings of the computer. The problem lies in the connection between the computer and the network. Therefore, we should check the network cable and the interface status of the hub and the hub, when we have built a small local area network, in order to make the network run normally, network maintenance is particularly important.

Due to the complexity of network protocols and network devices, many failures are not as simple as solving single machine failures. Locating and eliminating network faults requires not only long-term knowledge and experience accumulation, but also a series of software and hardware tools, and more importantly, your wisdom. Therefore, every network administrator should learn more about the latest knowledge, and this article will show you how to use the Windows command line to quickly detect and troubleshoot network faults.

Run the ping command to troubleshoot the NIC.

Use the ping command to ping the local IP address, loopback address) or computer name (for example, zhddsn) to check whether the NIC and IP network protocol are properly installed.

If it can be pinged, it means that there is no problem with the network card and network protocol settings of the computer. The problem lies in the connection between the computer and the network. Therefore, you should check the network cable and the interface status of the hub and the hub