Digital multimeter measurement capacitance has no resistance value how to repair

Looking for faults should be first outside and then inside, easy first and then difficult, and the whole should be broken into zero, and the key breakthroughs should be made. The methods can be roughly divided into the following types:1

Sensory method directly judges the cause of the fault by virtue of the senses, and through visual inspection, it can find such as wire breakage, desoldering, lap short circuit, fuse tube breakage, burnt components, mechanical damage, copper foil warping and fracture on the printed circuit, etc.; You can touch the temperature rise of the battery, resistor, transistor, and manifold block, and refer to the circuit diagram to find out the cause of the abnormal temperature rise. In addition, you can also check whether the components are loose, whether the integrated circuit pins are firmly inserted, and whether the transfer switch is cassette; You can hear and smell the presence or absence of strange sounds and odors. 2.

Voltage measurement method measures whether the working voltage of each key point is normal, and the fault point can be found quickly. For example, measure the working voltage and reference voltage of a D converter. 3.

Short-circuit method The short-circuit method is generally used in the method of checking the AD converter mentioned above, and this method is used more when repairing weak current and microelectric instruments. 4.Circuit Breaker Disconnects the suspicious part from the whole machine or unit circuit, and if the fault disappears, it means that the fault is in the disconnected circuit.

If necessary, replace the component with a good one, if the fault disappears, it means that the component is broken. 6.The interference method uses the induced voltage of the human body as the interference signal to observe the changes of the liquid crystal display, and is often used to check whether the input circuit and the display part are intact.

Second, repair skills for a fault instrument should first check and judge whether the fault phenomenon is common (all functions can not be measured), or personality (individual function or individual range), and then distinguish the situation, symptomatic solution.

Are you sure the multimeter is in capacitance mode? And the range is right?

Using a digital multimeter to measure the resistance, it shows a negative value (the meter is not broken), what is going on?

Using a digital multimeter to measure the resistance, it shows a negative value (the meter is not broken), what is going on? Hello dear, this may be caused by your measurement when the resistor is live. To measure the resistance, it is necessary to detach the resistance from the circuit, which can not be measured.

At this time, there is a weak voltage between the red and black watch pen, when the resistance is measured, the current of the red watch pen flows to the black watch pen, and the digital multimeter shows the resistance value after calculating the current, and the normal display is equal to or greater than 0. When the ** (live) measurement, there is a voltage at both ends of the resistance, when the meter pen is placed at both ends of the resistance, the current of the original circuit will be introduced into the multimeter, if the current at this time is reversed and greater than the current transmitted by the meter, there will be a negative phenomenon. I hope I can help you with the spikes.

If my answer is helpful to you, please give a thumbs up (in the lower left corner), I look forward to your like, your efforts are very important to me, and your support is also the motivation for my progress. Finally, I wish you again good health and a happy mood!

This is because the capacitor has a certain resistance value, if the capacitor has no resistance value becomes 0, then it means that there has been a short circuit between the internal plates, if the capacitance is measured to show "1", it means that the capacitance between the plates is open, so the capacitor will have a charging and discharging process, such as the red label is connected to the positive pole, and the black watch pen is connected to the negative pole, at this time it is to charge the capacitor, to a certain time, the value will not move, then the meter pen will be replaced, at this time the multimeter will ring, and then the number will be displayed, which is the capacitor in the discharge. It proves that this capacitor is good.

The capacitor is broken and unusable. Normally, the watch pen should be moved back to infinity. This would not be the case with an electronic watch. Capacitors must not work.

This capacitor has been internally short-circuited (possibly caused by breakdown in use) and cannot be used. If the capacitance of a normal capacitor is small, it is measured with a multimeter resistance level, because the charging time is very short, and the charging process cannot be seen, and the resistance is directly infinite; When measuring the large capacitor with the ohm range, you can see that there is a charging process in which the resistance value changes from small to large until infinite, and the larger the capacitance, the greater the internal resistance of the multimeter, and the longer the process time.

If you zero the meter, then the meter pointer points to the zero scale on the right side with the zero adjustment method (before using the multimeter, you should first perform "mechanical zeroing", that is, when there is no measured electricity, make the multimeter pointer point at the position of zero voltage or zero current.) Before measuring the resistance, short the two stylus and adjust the "ohmic zero knob" at the same time so that the pointer is just at the zero position to the right of the ohmic scale. If the pointer cannot be adjusted to the zero position, it means that the battery voltage is insufficient or there is a problem inside the meter.

And every time you change the magnification gear, you have to zero the ohms again to ensure the accuracy of the measurement. ）

Illustrate the capacitive pathway, just like a wire.

Resistance Measurement:1Insert the black watch pen into the COM jack and the red watch pen into the V jack. 2.Put the function switch on the range and connect the test pen to the resistor to be measured.

Note:1If the value of the resistance to be measured exceeds the maximum value of the selected range, an overrange "1" will be displayed, a higher range should be selected, for resistance greater than 1m or higher, it will take a few seconds for the reading to stabilize, which is normal.

2.When there is no good connection, such as an open circuit situation, the meter is displayed as "1".3.

When checking the impedance of the line under test, make sure that all power supplies in the line under test are removed and all capacitors are discharged. If there is a power supply and energy storage components in the line under test, it will affect the correctness of the line impedance test. 4.

The 200m gear of the multimeter has 10 words when it is short-circuited, and when measuring a resistance, these 10 words should be subtracted from the measurement reading. If a resistor is measured, it is displayed as.

Ten words should be subtracted from it. The actual resistance of the component under test is 100m.

Capacitance test: Before connecting the capacitor to be tested, it takes time to reset the range each time, and the presence of drift readings will not affect the test accuracy. 1.

Set the function switch in the capacitance range c(f)2Insert the capacitor into the capacitor test socket Note:1

The instrument itself has set up the protection of the capacitor file, so there is no need to consider the polarity and capacitor charge and discharge during the capacitance test. 2.When measuring capacitance, insert the capacitor into the dedicated capacitance test socket (do not insert the pen jack com, v).

3.It takes some time to stabilize the reading when measuring large capacitances. 4.

Unit conversion of capacitance: 1 F = 1000,000 pF

lμf=1，000nf

Hit the resistor and capacitor respectively, find the adaptation range, measure directly, and read.

After the power-on is completed, the two meter pens are exchanged for measurement.

Digital tables are like this, and they don't stay constant all the time.

20k20m

It's a different gear, which is the range.

This can be caused by the measurement when the resistor is live.

It is estimated that it is measured in red, and there is also direct electricity.

Use the resistance ohm file of the digital multimeter, and discharge the measured capacitor before testing to prevent damage to the digital multimeter. The two stages of the capacitor are not connected, and it is best to connect them with appropriate resistors.

Capacitance measurement: Use the resistance gear to select the appropriate range according to the capacitance capacity, and pay attention to the positive electrode of the capacitor for the electrolytic capacitor black meter pen when measuring.

Estimate the capacitance of microwave capacitance: It can be judged by empirical or reference to the standard capacitance of the same capacitance, and according to the maximum amplitude of the pointer swing. For example, a capacitor of 100 F 250V can be estimated with a capacitance of 100 F 25V, as long as the pointer swings the maximum amount, the capacitance can be determined to be the same.

Estimate the capacitance of pico-level capacitance: use R 10k, but only capacitance above 1000pf can be measured. For capacitors of 1000pf or a little larger, as long as the watch hand swings slightly, the capacitance is considered sufficient.

Test whether the capacitor leaks: for more than 1,000 microfarnes, you can use R 10 gear to quickly charge it, and preliminarily estimate the capacitance capacity, and then change to R 1k gear to continue to measure for a while, at this time the pointer should not return, but should stop at or very close, otherwise there is leakage. For some timing or oscillation capacitors below tens of micromethods (such as the oscillation capacitance of color TV switching power supply), the requirements for its leakage characteristics are very high, as long as there is a slight leakage, it can not be used, at this time, you can use the R 1k file after charging, and then use the R 10k file to continue to measure, the same watch hand should stop at the place and should not return.

Use ohmic gear, use two markers to point the capacitor on both feet, and see that the resistance of the capacitor will change from small to large, which proves that the capacitance is still good, and the resistance does not change, and the capacitor may be bad. Because I don't know what the capacitance is, I have to try it a few more times.

Very simple and practical capacitance measurement quality judgment method, multimeter does not have a capacitance file, how to use the resistance file to judge its quality, novices can understand at a glance!

First of all, the capacitor is discharged, measured in 10 ohms, and the watch hand will swing at the moment of contact, and then return to infinity. If it does not swing it is an open circuit, and if it does not reverse to infinity, it is a leakage or short circuit. The larger the capacity, the greater the swing. The above method is limited to measuring the capacitance of more than one micrometer.

The digital multimeter pen measurement resistance is not working, and the current measurement is normal.

Hello dear. The digital multimeter pen measurement resistance is not passable, and the normal reasons for measuring the current are as follows: The resistance value is not particularly large when used as a "current limiting" resistance in the general circuit, so the resistance value can be measured with the ohm file of the multimeter. If the resistance file of the multimeter is measured and the display is not working, then the source of the resistor is open (burned out) is stupid.

When measuring the resistance with a multimeter, a current is applied to the resistor, and then the resistance value is determined according to the voltage drop (voltage) of the current on the resistor hail. That is, the process of measuring the resistance is actually measuring the voltage at both ends of the resistor. If the resistor itself is charged (voltage), the measured voltage does not reflect the resistance value.