Which resistance does voltmeter V measure, why, and how is it identified?

The relationship between R1 and R2 is in parallel, and the voltage at both ends of them is equal.

Therefore, the V meter is connected to both ends of R1 (R2), and the voltage of R1 and R2 is on both sides.

In the third year of junior high school, you should not consider the internal resistance of the power supply.

So the V-meter also shows the supply voltage.

Note: High school is to consider the internal resistance of the power supply, so V is only the road-end voltage, definitely not the power supply voltage).

Judgment method: V table and who is connected in parallel (its two ends and whose two ends are the same contact), V table shows whose voltage at both ends.

Detailed enough, right? Hope you help!

For the ideal power supply and the ideal voltmeter, in principle, the voltmeter and whoever is connected in parallel is to measure whose voltage. Parallel connection means that both ends of the appliance are connected together.

The voltmeter in the figure is connected in parallel with R1 and R2, because R1 and R2 and both ends of the voltmeter are connected together, so the test voltage of the voltmeter is the R1 voltage and the R2 voltage.

The direction of the current is that the power supply is coming out positively into R1, the voltmeter, R2, and then converging into the negative power supply.

The voltage of the two resistors in the circuit is the same, and their voltages are measured, because the two ends of the two resistors are connected at the same point, so the point is the same, and the voltage at the end is also the same. The current comes out of the positive pole and flows into both resistors at the same time, and then back to the negative pole.

It measures the voltage of R1, R2 and the voltage source.

In essence, the voltmeter is also a resistor, and its resistance value is generally in the order of 1,000,000 ohms, so for the first year of junior high school, it can basically be considered that it is interrupting the circuit in the circuit. How did it flow in? The current comes out of the positive end of the power supply, divides into three strands, passes through three branches, and returns to the negative end, one of which passes V.

<> find a component connected in parallel to the voltmeter, and measure the voltage of that element. In the diagram, it is clear that the resistor R2 is connected in parallel with the voltmeter, so the voltage across the resistor R2 is measured.

Multi-purpose table reading method.

Resistance measurement: The multimeter dial is generally marked with 3 4 groups of scale marks, generally the top is the ohm file, the ohm file of the scale is not read from left to right, but from right to left ......Infinity (this is the magnification).

When measuring the resistance, the electric potential of the black pen is high, and the median resistance is equal to the internal resistance!

<> current measurement: Turn the selector switch to the DC current level to be measured, and then connect the test pen in series in the circuit, and read the second tick mark.

The bottom gear is generally not used.

Note: There is another requirement for the use of all meters: choose a reasonable grade, so that the hands stay between the "1 3--- 2 3" on the dial scale. This is not a strict requirement, but this "principle" must be taken into account.

1.Gear shift must be zeroed: red and black pen shorted.

2.Try to choose an intermediate notch when reading.

3.Red in and black out.

4.When reading, the pointer reads which number in which compartment it is close to.

5.Except for the non-tenth part of the ohm range, it needs to be estimated.

1. Adjust the baseline to zero.

2. Use standard probes, do not add measurement accessories at will.

3. Use equipment with a high following frequency.

4. Do a good job of anti-interference measures.

Choose an oscilloscope with the right bandwidth (not a larger bandwidth, the better), choose the right voltage probe, and choose the right trigger settings.

Summary. According to Ohm's law, the output voltage at both ends of the resistor is equal to the current flowing through the resistor multiplied by the resistance of the resistor. It is assumed that there is nothing wrong with the voltmeter used to measure the output voltage across the resistor.

If the voltmeter shows that the output voltage at both ends of the resistor is changing, there are two possible scenarios, one is that the current flowing through the resistor is changing, or the resistance value of the resistor itself is changing. In either case, the output voltage across the resistor will change. Hope it helps.

A resistance meter measures why the resistance shows voltage.

According to Ohm's law, the output voltage at both ends of the resistor is equal to the current flowing through the resistor multiplied by the resistance of the resistor. It is assumed that there is nothing wrong with the voltmeter used to measure the output voltage across the resistor. If the voltmeter shows that the output voltage at both ends of the resistor is changing, there are two possible scenarios, one is that the current flowing through the resistor is changing, or the resistance value of the resistor itself is changing.

Is voltage anti-dependent voltage?

1. The withstand voltage is the ability of the live part to withstand elegance between the chassis, and the power frequency withstand voltage of the general product is more than 50kV under special circumstances. 3. Measure with a withstand voltage meter, select the model according to the range, and the withstand voltage meter will apply a specified AC or DC high voltage between the live part and the non-live part of the electrical appliance (generally the shell) to check the withstand voltage capacity of the insulating material of the electrical appliance. The withstand voltage test generally does not affect the performance of the insulating material.