How do I use a voltmeter? Follow his principles .

1) Observe whether the pointer of the voltmeter is on the zero line, if not, you can use a screwdriver to adjust the adjustment nut under the dial so that the pointer points to the zero line.

2) Estimate the size of the measured voltage, choose the appropriate range of the voltmeter, the measured voltage value is about equal to 70% of the range, the measurement effect is the best, if the size of the measured voltage can not be estimated, you can start from the maximum range.

3) After selecting the range, the voltmeter is connected in parallel at both ends of the measured voltage circuit, so that the current flows from the "+" line binding post, and flows out from the "-" binding post, if the "+" binding post of the voltmeter is reversed, the pointer of the voltmeter will swing in the opposite direction, so that not only can not measure the size of the voltage, but also may break the pointer of the voltmeter.

4) Connect the voltmeter into the circuit correctly, do not rush to close the switch for measurement, use the moving contact of the switch to try the static contact of the switch, and observe the pointer of the voltmeter.

If the voltmeter pointer does not move, it means that there is an open circuit in the circuit, and the connection of the circuit should be checked, especially whether the binding post is in good contact.

If the voltmeter pointer is deflected in the opposite direction, it means that the "+" binding post of the voltmeter is reversed and should be reconnected.

If the voltmeter pointer is deflected too much and exceeds the maximum value of the selected range, it means that the selected range is small and should be replaced with a larger range.

If the deflection of the voltmeter pointer is too small, not even to a small range, it means that the selected range is large and should be changed to a smaller range.

Should wait for the voltmeter pointer to stabilize before reading, reading should let the line of sight through the pointer and the dial perpendicular, now some voltmeters change to use liquid crystal display, to the reading has brought greater convenience.

The voltmeter can be directly connected to the two poles of the power supply to measure the voltage of the power supply, when the power supply is working, it provides a certain voltage value to both ends of the circuit, and the voltage value provided will be reduced with the extension of the use time, so the voltmeter is often directly connected to the two poles of the power supply to measure the voltage value provided by the power supply.

5) If it is an AC voltmeter, you don't have to distinguish between positive and negative poles, just select the range.

Connect the voltmeter in parallel with the electrical appliance, see the positive and negative binding posts clearly, don't connect them in reverse, and see the range indexing value clearly. Choose a large number of test touches.

Is it the kind of voltmeter of physics?

In series with electrical appliances. A voltmeter can only measure the voltage of one electrical appliance.

The voltmeter has two rods, one red and one black, with a black plug in com. The red color is inserted into the red hole in the adjacent com, and the voltmeter selects the corresponding voltage level and the number of voltage poles before measuring the voltage. Whether it's AC or DC.

If you are unsure about the size of the voltage, it is recommended to put the voltage in the maximum range. When the voltmeter is used up, put the gear in the maximum range.

Before the voltmeter is used, the pointer of the meter should be adjusted to zero, so the statement is correct;

When the voltmeter measures the voltage, it must be connected in parallel with the shouted test circuit, so the statement is wrong;

When the voltmeter measures the voltage, it must be connected in parallel with the circuit under test, so the statement is correct;

The measured voltage value cannot exceed the maximum measured value of the voltmeter, which is true;

The voltmeter can be used to measure the power supply voltage of the direct stove seepage, so it is wrong;

When connecting the voltmeter to the circuit, note that the current must flow from the "+" binding post; The statement is correct, so choose D

Before the voltmeter is used, the pointer of the meter should be adjusted to zero, so the statement is correct;

When the voltmeter measures the voltage, it must be connected in parallel with the circuit under test, so the statement is wrong;

When the voltmeter measures the voltage, it must be connected in parallel with the circuit under test, so the statement is correct;

The measured voltage value cannot exceed the maximum measured value of the voltmeter, which is correct;

The voltmeter can be used to directly measure the voltage of the power supply, so it is wrong;

When connecting the voltmeter to the circuit, note that the current must flow from the "+" binding post; The statement is correct, so choose D

1) The voltmeter must be connected in parallel with the electric chain of the unit to be measured;

2) The current should flow from the positive terminal of the voltmeter and flow out from the negative terminal of the voltmeter;

3) The measured voltage cannot exceed the range of the voltmeter

c. According to the use of the voltmeter, the statements of a, b and d are correct; C is wrong, no matter which range is chosen, the current must be entered by the "+" binding post, and the "- binding post is out, so C is selected

Voltmeter principle.

The greater the magnetic force generated, the greater the swing of the pointer on the voltmeter, there is a magnet and a wire coil in the voltmeter, after passing the current, the coil will produce a magnetic pants rough field, and the coil will be deflected under the action of the magnet after being energized, which is the head part of the ammeter and voltmeter.

Because the voltmeter should be connected in parallel with the sensitive resistance of the electric stool under test, if the sensitive galvanometer is directly used as a voltmeter, the current in the meter is too large, and the meter will be burned out, and then a large resistance needs to be connected in series in the internal circuit of the voltmeter, so that after the transformation, when the voltmeter is connected in parallel in the circuit, due to the effect of resistance, most of the voltage added to both ends of the meter is shared by the resistance in series, so the current through the meter is actually very small, so it can be used normally.