Can the voltmeter measure the voltage at both ends of the wire?

It is not possible to use a voltmeter directly, because the resistance of the wire is very small, and the terminal voltage is very small, which cannot be measured directly with a general voltmeter. But there's a way to do it. That is, a high-gain difference amplifier with a high magnification is connected to both ends of the wire, and the terminal voltage of the wire can be measured.

For example, the voltage drop of the wire is 1mV, and the voltage is 1V after 1000 times differential amplification, so that the voltage drop (or terminal voltage) of the wire can be indirectly measured. Of course, the current of the circuit is measured, killing two birds with one stone.

OK! The voltmeter is actually composed of a meter head and a resistor, and theoretically it is possible to directly measure the voltage of the two sections of the wire. However, the resistance of the wire is equivalent to the internal resistance of the voltmeter. Otherwise, it is easy to damage the voltmeter.

Yes, indirect current measurement.

However, if the resistance of the wire is very small, it is not something that can be measured by an ordinary voltmeter.

It depends on the length of the wire, if the wire is long enough, the resistance is large, and the voltage drop is large, it can be measured. For example, the coils of some electrical appliances are made of long wires. If the wire is short and there is almost no voltage drop, the voltmeter will not be able to measure it.

It cannot be directly connected to the ...... at both ends of the wireThe wires will burn out the ...... the voltageBecause the voltage converter has an internal power supply

There must be a resistor between the voltmeter 2 meter pens.

Yes, but the voltage is small.

Because the current is the same, the resistance is very small, so the voltage is small.

Because i=u r but there must be electrical appliances in the circuit.

Otherwise, the power supply will be burned out.

The voltmeter should have a very small range.

Normally, it can be measured, if the power supply voltage is small, but because the resistance of the wire is small, the current may be large, and the power supply may be burned out. But if it is controlled, it is possible, but it is not advocated.

Hello dear, glad to answer for you [pleasant]. Can the pro-pro voltmeter be directly connected to both ends of the power supply, and the voltmeter can be directly connected to both ends of the power supply, that is, from the formal point of view, it is equivalent to parallel connection with the power supply. Voltmeter is an instrument for measuring voltage, and the commonly used voltmeter - voltmeter symbol:

v, inside the sensitive galvanometer there is a permanent magnet, between the two binding posts of the galvanometer a coil made of wires in series, the coil is placed in the magnetic field of the permanent magnet, and is connected to the pointer of the meter by a transmission device. Most voltmeters are divided into two ranges. The voltmeter has three binding posts, one negative binding post, two positive binding posts, the positive pole of the voltmeter is connected with the positive pole of the circuit, and the negative pole is connected with the negative pole of the circuit.

The voltmeter must be connected in parallel with the appliance under test. The voltmeter is a fairly large resistor, ideally thought of as an open circuit. The voltmeters commonly used in laboratories at the junior high school level have ranges of 0 3 V and 0 15 V.

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First of all, we must know that in the voltmeter, there is a magnet and a wire coil, after passing the current, the coil will produce a magnetic field, so that the coil will rotate under the action of the magnet after being energized, which is the head part of the ammeter and voltmeter.

The current that can pass through this meter is very small, and the voltage that can be borne by both ends is also very small (certainly much less than 1V, maybe only 0.00 volts or even smaller), in order to be able to measure the voltage in our actual circuit, we need to connect a relatively large resistance to this voltmeter in series to make a voltmeter. In this way, even if a relatively large voltage is added to both ends, most of the voltage is applied to the large resistance we add, and the voltage on the meter head will be very small. This makes it possible to measure directly across both sides of the power supply.

The voltmeter can be connected directly to the power supply at both ends to measure the power supply voltage, because the resistance of the voltmeter is very large, and there is no short circuit in the power supply.

Because the voltmeter should be connected in parallel with the measured resistance, if the sensitive galvanometer is directly used as the voltmeter, the current in the meter is too large, and the meter will be burned out, so that 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.

The symbol of the DC voltmeter should be added with a " under v "The symbol of the AC voltmeter should be added with a wavy line under v ".

The method is dead, the key depends on your understanding and application, I hope the following methods can help you.

A method for determining whose voltage is being measured by a voltmeter.

1. "Box" method: When the voltmeter and the electrical appliance form a box, the voltmeter measures the voltage at both ends of the electrical appliance;

When the voltmeter and the power supply only form a box, the voltmeter measures the voltage at both ends of the power supply;

When the voltmeter, electrical appliances and power supplies form a box together, the voltmeter measures the voltage at both ends of the electrical appliances and electrical appliances other than the power supply.

2 "Short circuit method": the voltmeter is regarded as a piece of wire, according to the flow direction of the current to see who short-circuited, then the voltmeter is to measure the voltage at both ends.

3. Component open circuit method: that is, first remove the power supply in the circuit diagram so that it cannot form a closed loop, and then regard the voltmeter as a power supply, and see which electrical appliance can form a closed loop with the voltmeter, then the voltmeter will measure the voltage at both ends of the electrical appliance.

The voltmeter can be directly connected to the power supply at both ends to measure the power supply voltage This is because the resistance of the voltmeter is very large, and the voltmeter can be regarded as a disconnected circuit when analyzing the weight circuit

In the use of voltmeter, the voltmeter can be directly connected to the two poles of the power supply, which is used to measure the voltage between the two poles of the power supply; This is because the resistance of the voltmeter is very large, and when analyzing the circuit, the voltmeter can be regarded as a disconnected circuit; It will not cause a short circuit in the circuit.

The internal resistance of the voltmeter is large (even if the current passing through the meter is approximately zero even when crossed over very high voltages), and it has little effect on the power supply when measured at both ends of the power supply.

The internal resistance of the voltmeter is large. As large as a voltage of tens of volts. It can be considered that the circuit is broken. Therefore, it can be directly connected to both ends of the power supply. And the ammeter is because the resistance is very small. If it is directly connected to both ends of the power supply, it will short-circuit.

The voltmeter directly measures both ends of the power supply, and the measured voltage is the voltage at the power supply end. Due to the large internal resistance of the voltmeter, the current generated during the measurement is very small and almost negligible. For example, the image below:

R0 is the internal resistance of the power supply, and R is the internal resistance of the voltmeter. At this point the current is 12 voltmeter readings.

If the power supply and the consumer form a circuit, assume that the equivalent resistance of the consumer is 10:

The load is connected in parallel with the voltmeter, the resistance is about 10, the current is 12 (10+, and the power supply voltage drop is about.

The voltage measured by the voltmeter is:

The no-load measurement power supply is 12V, plus 10 ohm load, and the supply voltage is. That's it.

There will be a voltage drop in the line, and the supply voltage and the load side voltage will be different.

The voltmeter is directly connected to the power supply to measure the voltage, which can be regarded as the "open circuit voltage" of the power supply, that is, the voltage at both ends of the power supply is approximately equal to the electromotive force of the power supply when the power supply basically has no output current. However, when the voltmeter measures the input voltage at both ends of the circuit, if the circuit is working, that is, the power supply has an output current, due to the relationship between the internal resistance of the power supply, the output voltage of the power supply will be equal to the "open circuit voltage" minus the product of the output current and the internal resistance of the power supply (that is, the voltage generated by the output current on the resistance in the power supply), so the reading of the voltmeter at this time is less than the "open circuit voltage".

Hello! Both the internal and external connections of the voltmeter have a certain impact on the measurement results.

First of all, internal connection means that the voltmeter is directly connected to the circuit for measurement, and the internal resistance of the voltmeter has an impact on the measurement results. The greater the internal resistance of the voltmeter, the smaller the shadow impact on the circuit, and the more accurate the measurement results. When connected internally, the voltmeter will consume a part of the current, which will have a certain load effect on the circuit.

If the internal resistance of the voltmeter is too small, it will cause the voltage of the circuit to drop, resulting in a small measurement. However, if the internal resistance of the voltmeter is too large, the voltage of the circuit will rise, and the measurement result will be too large.

In addition, external connection refers to the connection between the voltmeter and the circuit through a cable, and the resistance of the cable has an impact on the measurement results. The greater the resistance of the cable, the greater the voltage drop is introduced, resulting in smaller measurements. And if the resistance of the cable is smaller, the less the voltage drop and the more accurate the measurement.

In addition, there are a number of other factors that can also have an impact on the measurement results. For example, a change in temperature can cause a change in the internal resistance of a voltmeter, which can affect the accuracy of the measurement. At the same time, the accuracy and sensitivity of the voltmeter also affect the accuracy of the measurement results.

In summary, both the internal and external connection of the voltmeter will have a certain impact on the measurement results, including factors such as internal resistance, cable resistance, temperature change, and instrument accuracy. In order to ensure the accuracy of the measurement results, we should choose the right voltmeter, the right connection, and pay attention to the influence of environmental conditions.

Hope the above meets your needs, if you have any other questions, please feel free to ask me.

Of course. When the internal resistance of the voltmeter is not negligible, the current of the external meter of the voltmeter may make the measurement resistance smaller!