In what case, the resistance of the sliding rheostat increases, and the indication of the ammeter an

In series circuits, when the resistance of the sliding rheostat increases, the current must decrease. That is, the indication of the ammeter must be reduced.

If the voltage of the sliding rheostat is measured, it will become larger, and if the voltage of the fixed value resistance is measured, it will decrease.

The reason is that the constant value resistance must be moved by Ohm's law: that is, when the resistance is constant, the current is proportional to the voltage, which means that the current is small, and the voltage must be small.

Therefore, when the fixed resistor voltage is small, the rheostat voltage is large, because the sum of voltages is constant. At this time, if the voltage of the resistor is fixed in the voltmeter, the count is small, and the voltage of the rheostat is measured, which is the indication is large.

When the circuit of voltammetry resistor is selected, the resistance of the sliding rheostat becomes larger, the current indication number becomes smaller, and the voltage indication number becomes larger.

Put the voltmeter of the volt-ampere resistance measurement circuit, and when the two ends of the sliding rheostat are sliding, the resistance value of the sliding rheostat becomes larger, the current indication number becomes smaller, and the voltage indication number becomes larger.

In principle, it has nothing to do with the supply voltage.

In the series circuit of the rheostat and the constant value resistor, the voltmeter measures the voltage at both ends of the fixed value resistor, the resistance of the sliding rheostat increases, and the indication of the ammeter and voltmeter decreases;

When the voltmeter measures the voltage at both ends of the rheostat, the resistance of the sliding rheostat becomes larger, the current indication number becomes smaller, and the voltage indication number becomes larger.

The slide resistor moves, the voltage indication does not change, and the ammeter has no indication.

1) When measuring the resistance with voltammetry, the voltmeter should be connected in parallel with the resistance to be measured; (2) Close the switch after connecting the circuit, and find that the readings of the two meters have not changed accordingly, the reason: it may be that the sliding rheostat is not connected "one up and down", it may be that the ammeter is connected in parallel with the sliding rheostat, and it may be that the ammeter and the voltmeter are swapped, etc. There is no "one-up-down" connection for sliding rheostats (or parallel connection of ammeter to sliding rheostat, or switch position of ammeter and voltmeter, etc.).

The dynamic rheostat changes its own resistance, its principle is to change the length of the resistance wire of the access circuit, the principle of it changes the voltage is U=IR, when the sliding rheostat R increases, the voltage allocated to it also increases, but the total voltage of the circuit does not change, so the voltage distributed to the electrical appliance decreases, the voltmeter measures the voltage of the electrical appliance, so the indicator decreases, the current of the series circuit is constant, when you increase the resistance of the sliding rheostat, it also increases the total resistance of the circuit, because the voltage at the end of the road remains unchanged, By the formula U=IR, U does not change, R increases, so i decreases.

Addendum: What do you mean by keeping the voltage constant? If the voltage at the end of the road is unchanged, change the fixed value resistance, slide the slide, so that the voltage at both ends of the fixed value resistance is constant, we first set it to U, when the fixed value resistance changes, the current through the resistance also changes (U = IR, you are constant, R increases, so i decreases), because the series circuit, so the current everywhere is equal, so it can be said that the circuit current changes.

The principle is the same as the position of the sliding vane of the mobile sliding rheostat, but this can accurately determine the resistance value of the value of the resistor, so as to draw more accurately, the general test may be done because you do not know the internal resistance of the ammeter (the problem of internal resistance is high school knowledge, junior high school and pass by), afraid that the ammeter will burn out, and there is a possibility that the voltage at the end of the road is not easy to control, or too large, beyond the range of the voltmeter, so it is necessary to use a sliding resistor to control the voltage at both ends of the fixed value resistor, The reason for replacing electrical appliances with fixed-value resistors is that the voltage at both ends of the electrical appliances exceeds the rated voltage of the electrical appliances, resulting in excessive output power of the electrical appliances and burning the electrical appliances.

Is that what you mean?

I'll teach you a universal approach :

Come to an end! This method can introduce the voltage, current, and meter indication of each electrical appliance in the complex hybrid circuit of multi-use appliances and meters.

According to Ohm's law i=u r when the voltage is constant, the current is inversely proportional to the resistance. Therefore, the greater the total resistance in the series circuit, the smaller the current, and the voltage at both ends of the sliding rheostat naturally decreases. But the power supply voltage is the same, as was the case in our junior high school years.

When the sliding rheostat is connected in parallel with the consumer, the resistance value of the sliding rheostat becomes larger, and the current passing through it decreases, and the voltage is the power supply voltage or unchanged. The total current decreases.

When a circuit is connected in series.

1) When the voltmeter measures the sliding rheostat, the power supply voltage remains unchanged, then when the sliding rheostat becomes larger, the voltage will increase with it, because the resistance becomes larger, so the current will become smaller. When the sliding rheostat becomes smaller, the voltage becomes smaller, the total resistance decreases, and the current decreases.

2) When the voltmeter measures other electrical appliances, the power supply voltage remains unchanged, then when the sliding rheostat becomes larger, the voltmeter becomes smaller, the total resistance becomes larger, and the ammeter becomes smaller.

When circuits are connected in parallel. The sliding rheostat becomes smaller, the voltmeter becomes larger, the total resistance becomes smaller, and the ammeter becomes larger.

The voltages are equal everywhere, so no matter how much the sliding rheostat changes, it will not change the voltage.

Then when the sliding rheostat becomes larger, just like in series, the total resistance becomes larger, and the current becomes smaller.

If the voltage of other electrical appliances is measured, when the resistance increases, the voltmeter and current indication number decrease.

Are the currents and voltages you ask the quantities of the sliding rheostat or the quantities of other consumers connected in series or parallel with it?

If the amount of sliding rheostat is simple, when used in series, the resistance becomes larger, the current becomes smaller, and the voltage distribution also decreases.

When used in parallel, the resistance becomes larger, the current decreases, and the voltage does not change. = The total voltage is constant.

When the hybrid is used, you didn't ask, and you didn't take the test in junior high school. It's too much trouble, let's not talk about it.

If you are asking about the voltage and current changes of other electrical appliances connected in series and parallel, when used in series, the slip resistance becomes larger, the current becomes smaller, and the slip voltage also decreases, then the other voltages become larger. There is a complementary relationship between the partial voltages, you are big and I am small, you are small and I am big, and the sum of the total voltage.

When used in parallel, the slippery resistance becomes larger, the current becomes smaller, and the slippery voltage does not change. = The total voltage is constant. Then the electrical appliances connected in parallel with it have not changed anything, and the parallel circuit branches do not affect each other!!

When the hybrid was used, you didn't ask, and you didn't take the test in junior high school. It's too much trouble, let's not talk about it.

1. The sliding rheostat is broken. Because it's on the main circuit, it's the equivalent of a switch being disconnected.

2. It is short-circuited. Because at this time, it is no longer effective to regulate it, and the current will indeed be relatively large when it is short-circuited, which is equivalent to the power supply voltage directly connected to the bulb.

3. The small bulb burned out. This is equivalent to the voltmeter directly connected to both sides of the power supply, at this time, due to its large internal resistance, so the ammeter is almost 0. When the voltmeter is connected directly to both ends of the power supply, it reads the supply voltage.

4. (1) Smaller, larger, darker. Because the voltmeter and the bulb are connected in series at this time, its resistance is very large, so the current of the bulb is very low, and the bulb is also short-circuited by the ammeter, so in fact, the bulb is off at this time, and the ammeter has almost no indication.

2) Same as question 3, the light bulb burned out. Or you can write "light bulb breaks".

1 The current indication is normal but the voltmeter has no indication:

"The current indication number is normal" indicates that the main circuit is the path, and "the voltmeter has no indication number" indicates that no current passes through the voltmeter, then the cause of the fault may be: The voltmeter is damaged; Poor contact of voltmeter; Electrical appliances connected in parallel to the voltmeter are short-circuited.

2 The voltmeter has an indication but the ammeter does not.

"The voltmeter has an indicator" indicates that there is current passing through the circuit, and "the ammeter has no indicator" indicates that there is no or almost no current flowing through the ammeter, then the cause of the fault may be: short circuit in the ammeter; The electrical appliance connected in parallel with the voltmeter is open, and at this time, a large resistance (voltmeter internal resistance) is connected in series in the circuit where the ammeter is located, so that the current is too small, and the ammeter does not display the number clearly.

3. There is no indication for ammeter and voltmeter.

There is no indication in both meters" indicates that there is no current passing through the two meters, in addition to the short circuit of both meters at the same time, the biggest possibility is that the main circuit is open and there is no current.

For your reference, I forgot it all...

Open; The wires are connected above or below the rheostat; Short circuit; 0, increase, dim, light disconnection.

Summary. Hello, to keep the indication of the voltmeter unchanged, you can only reduce the current in the circuit and increase the resistance of the sliding rheostat to the circuit, that is, the slider p moves to the right I hope mine is helpful to you.

2. In the experiment, if the 10 resistance is replaced by 5 resistance, how will the voltage representation change? How to adjust the sliding rheostat.

Hello, to make the voltmeter unchanged, you can only reduce the current in the circuit, increase the resistance of the land side wheel of the large sliding rheostat connected to the circuit, that is, the sliding blade p moves to the right end I hope mine is helpful to your early letter.

3. If the sliding rheostat is adjusted in the experiment, the brightness of the bulb is always dim, what is the reason?

4. The original resistance of a wire is 10, and now it is cut and only half is retained, how much resistance has become?

Hello, there are many reasons for this, and I don't have time to explain them all for you.

When the resistance of 15 is replaced by a resistance of 10, the total resistance of the series circuit decreases, according to Ohm's law.

It can be seen that the current in the circuit increases, and the rheostat slides.

The voltage obtained becomes larger, and the voltage obtained by the resistance decreases, so the slider should be adjusted to move to the right to reduce the resistance of the sliding varistor connected to the orange circuit, so that when the indication of the voltmeter reaches the point, the ammeter is read.

Indication So the answer is: become smaller; Adjust the resistance of the sliding rheostat so that the indication of the voltmeter is equal to.

When the sliding rheostat slider p moves to the right, the resistance value of the sliding rheostat access circuit becomes larger;

According to the series characteristics of the resistors, the total resistance in the circuit becomes larger;

According to Ohm's law, when the voltage is constant, the current in the circuit becomes smaller, that is, the indication of the ammeter becomes smaller;

According to U=IR, the voltage at both ends of the resistor R becomes smaller, so the number of the voltmeter becomes smaller, so D is selected

The instrument for measuring voltage is: voltmeter, and its rules of use are: voltmeter should be connected in parallel in the circuit; The connection method of the terminal post should be correct, so that the current enters from the "+" terminal post and exits from the "-" binding post; The measured voltage should not exceed the range of the voltmeter;

2. The instrument for measuring the current is: the ammeter, and its rules of use are: the ammeter should be connected in series in the circuit; The connection method of the terminal post should be correct, so that the current enters from the "+" terminal post and exits from the "-" binding post; The measured current should not exceed the range of the ammeter; It is absolutely forbidden to connect the ammeter to the poles of the power supply without passing through the electrical appliance.

Pure hand play, I hope it helps you!