How to choose a slip resistor in the circuit, choose a large or small one

Sliding rheostats.

The selection is based on the working current of the controlled circuit (that is, the current flowing through the sliding varistor) to select the level of resistance and the size of the dissipated power (the maximum allowable current of the resistor). When the circuit is operating normally (normal operating current), the current that needs to flow through the resistor must be sliding through the resistor within a certain resistance range.

to select the appropriate resistance value to control and implement (the resistance is to control the current). Therefore, the range of variable resistance values of the sliding rheostat selected should include the resistance values required for the normal working current of the control circuit. Then there is the question of the maximum allowable current, to ensure that the current (or power) allowed through the sliding resistor is greater than the actual working current of the circuit.

Otherwise, the resistor will heat up. Burnt.

1. It can't be too small. The main thing is to look at the current in the loop. The current of the other equipment and the current of the rheostat must not exceed the rated current.

Second, it can't be too big. It is necessary to make the measuring instrument have a clear indication change. In short, there is no fixed selection method, and there are no advantages and disadvantages of large slip and small slip, and it is necessary to choose the appropriate one for specific experiments.

Looking at the rated current of the electrical appliance, when the resistance value of the sliding rheostat is at the maximum value of 1 2, the current in the line cannot exceed the rated current but it cannot be too small.

Consider the range of the ammeter and voltmeter.

To put it simply, move the terminal post closer to the direction below, and the resistance will increase; Move the terminal post away from the direction of the connection, and the resistance becomes larger.

If it is to observe the sliding rheostat in kind. First look at which side of the lower binding post is connected to the wire into the circuit, and then look at the position of the sliding blade, the farther away from the connected lower binding post, the greater the resistance; The closer it is, the less resistance it is.

If it's looking at the circuit diagram. Find the symbol of the sliding rheostat, then look at which side of the box is connected to the wire, and then look at the arrow representing the slide, if the arrow is closer to the side where the wire is connected, the resistance will be smaller. The opposite is the greater.

The key to judging the change in the resistance size of a sliding rheostat after sliding is to look at the change in the length of the resistance wire connected to the circuit. The resistance wire in the access circuit becomes longer, and the resistance becomes larger.

As shown in the figure, the sliding rheostat has four binding posts: A, B, C, and D. Neither the two binding posts at the upper end or the two binding posts at the lower end at the same time can change the resistance in the access circuit. The resistance in the access circuit can only be changed when using a "one-up and one-down" connection.

As shown in Figure A, the C and B binding posts are connected to the circuit, and the resistance wire of the access circuit is the CP segment. When the slide p moves to the right, the length of the CP resistance wire becomes longer, so the resistance in the access circuit becomes larger.

In Figure B, when the slide p moves to the right, the PD segment of the resistance wire becomes shorter, so the resistance of the access circuit becomes smaller.

The connection in Figure C is the same as in Figure B, and when the slide p is moved to the right, the resistance to the access circuit is also reduced.

To judge the change of resistance in the access circuit of the sliding rheostat, the key is to find the resistance wire in the access circuit, and then judge whether the resistance wire becomes longer or shorter when moving the slide, the resistance wire becomes smaller when the resistance wire becomes shorter, and the resistance wire becomes longer, and the resistance of the access circuit becomes larger.

How it works. Sliding rheostat is one of the commonly used devices in electricity, and its working principle is to change the resistance by changing the length of the resistance line of the part of the access circuit, so as to gradually change the magnitude of the current in the circuit. The resistance wire of the sliding rheostat is generally a nickel-chromium alloy with a high melting point and large resistance, and the metal rod is generally a metal with a small resistance, so when the resistance cross-sectional area is constant, the longer the resistance wire, the greater the resistance, and the shorter the resistance wire, the smaller the resistance.

Wait a minute. Teach you a simple method, the four binding posts of the sliding rheostat can only be used normally if they are connected to the upper and lower ones, the rheostat connected to the "upper" terminal is equivalent to a wire, and the same connected "lower" binding post is equivalent to a fixed value resistor. So we look at the sliding vane, and the farther away the sliding vane is from that binding post at the lower end of the wiring, the greater the resistance value, because the longer the resistance wire through which the current passes.

Conversely, the closer the slide is to the binding post at the lower end, the smaller the resistance.

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Give a thumbs up, dear.

Looking at the length of the resistance wire (a thin wire wound around the circular insulating tube of the sliding varistor) between the sliding end of the rheostat and one of the fixed ends of the active access circuit, if the resistance wire of the access circuit becomes longer, the resistance becomes larger, and vice versa. As for the voltage and current, it should be calculated according to Ohm's law, and the law that the current of the series circuit is equal everywhere, and the total voltage is equal to the sum of the voltages of the parts, and the voltage of the parallel circuit is equal everywhere, and the current of the trunk circuit is equal to the sum of the currents of the branches.

A voltmeter is connected in parallel at both ends of the sliding rheostat to change the position of the sliding vane, if the voltage indication number becomes larger, the resistance value of the sliding rheostat becomes larger, and conversely, the indication becomes smaller, the resistance value becomes smaller.

After connecting the circuit, according to the direction of current flow, look at the change of the length of the access section of the sliding rheostat, if the length becomes longer, the access resistance will become larger.

Look at whether the effective part of the circuit it connects to becomes more or less, if it is more, it becomes larger, otherwise it becomes smaller.

First of all, you need to understand the slip rheostat.

Role:1Control the voltage at both ends of the electrical appliance under test.

2.Regulates the current in the circuit.

3.Protection circuits.

There are three factors to consider when choosing the right sliding rheostat:

1. The access mode of the sliding rheostat.

2. Voltmeter in the circuit.

Ammeter measuring hall socks,

3. The total resistance in the circuit.

For the first. One, two. Consider the access of the sliding rheostat (parallel or series), so that the sliding rheostat can ensure the safety of the electric road regardless of sliding. And according to the topic, select the sliding rheostat that meets the standard

For point 3, roughly estimate the total resistance of the entire circuit, and choose a sliding rheostat that is similar to other resistors in the circuit, for example, if there is a 10 ohm resistance in the circuit, then the sliding rheostat 5-20 ohms is sufficient. Don't let the sliding rheostat change slightly to make the current and voltage of the entire circuit change too much, according to the analysis of the topic of combustion and volt.

I'm so tired of typing.!）

I am also a student, and we can work together on physics problems in the future. ·

Connect to point A, connect point C or point D, and the resistance becomes smaller when you go to the left.

There will definitely be an arrow on the end of the circuit diagram that is sliding. Then cut it directly with an arrow, cut the slip resistor in half, and turn it into two small resistors, so that it should be easy to see that one part is short-circuited, and the remaining half is connected to the circuit.

A sliding rheostat is a variable resistor. When the sliding rheostat is fully connected to the circuit, it is the maximum resistance, and it is generally believed that the maximum resistance is used when the following two binding posts are connected at the same time.

Let's tell you the idea first, just look at whether the resistance wire through which the current flows becomes longer or shorter, and I will analyze it for you.

First of all, it is clear that the wire is connected to the middle one and the middle one.

The effect is the same no matter who picks it up.

Then there are two scenarios.

1.Connect 3, move to the left, the resistance wire through which the current flows becomes shorter, and the resistance decreases by 2Connect 4, move to the right, the resistance wire through which the current flows becomes shorter, and the resistance decreases.

Access to point A ......Take out the ...... point C or point DThe resistance becomes smaller when ...... leftI want to answer yes.

……I'm supposed to be a ...... in the same grade as you

The connection method of the sliding rheostat is one up and one down, the left up and left are connected, and the sliding blade p moves to the right and the resistance increases; The upper right and lower left are connected, and the resistance of the slider p moves to the right and becomes larger; So when the next binding post is connected to the lower left, the slider p moves to the right and the resistance becomes larger. The upper left and lower right are connected, and the resistance of the slider p moves to the left and becomes larger; The upper right and lower right are connected, and the resistance of the slider p moves to the left and becomes larger; Therefore, when the lower binding post is connected to the lower right binding post, the resistance of the slider P moving to the left becomes larger.

General conclusion: When the sliding blade P moves in the opposite direction of the connecting lower binding post, the resistance becomes larger. (I don't have very good expression skills, and I am often trained by my math teacher and Chinese teacher together, so I hope you forgive me.) ）

To look at the wiring at both ends of the sliding rheostat, it is necessary to correctly determine which end of the sliding rheostat the current passes through, and judge whether it is a useful resistance 3: at this time, look at the sliding direction of the sliding rheostat to judge.

For example, the left side of the line of the sliding rheostat is connected to the top and the right side is connected to the bottom, then it can be concluded that the right side of the sliding blade is the useful resistance, and the sliding blade is sliding to the right side, the useful resistance increases, the resistance increases, and the useful resistance decreases to the right, and if the connection method is reversed, the result is the opposite.

Summary. Hello dear, when you change the resistance by sliding the rheostat, if the resistance becomes smaller, then the slider of the sliding rheostat will move to the side of the original position. Conversely, if the resistance becomes larger, the slider will move to the other side of the original position.

This is due to the fact that inside the sliding rheostat, the value of the resistance is achieved by changing the distance between the slider and the resistor. If the distance between the slider and the resistor is shortened, the resistance becomes smaller, and vice versa. So, when you move the slider, you can control the resistance of the resistor, and you can see if the resistance is increasing or decreasing by looking at the direction of movement of the slider.

Please pay attention to the check, thank you.

Hello dear, when you change the resistance by sliding the rheostat, if the resistance becomes smaller, then the slider of the sliding rheostat will move to the side of the original position. Conversely, if the resistance becomes larger, then the slider will move towards the other side of the original position. This is due to the fact that inside the sliding rheostat, the value of the resistance is achieved by changing the distance between the slider and the resistor.

If the distance between the slider and the resistor is shortened, the resistance will become smaller, and vice versa. So, when you move the slider, you are able to control the resistance of the resistor, and the resistance can be seen to increase or decrease by looking at the direction of movement of the slider. Please pay attention to the check, thank you.

Hello dear, a sliding rheostat (also known as a potentiometer or potentiometer) is an electrical component that adjusts the value of resistance in a circuit. Here are the advantages and disadvantages of sliding rheostats: Pros:

1.The resistance value of the sliding rheostat is adjusted by the position of the sliding electrical contact on the resistor resistance material, which can achieve relatively accurate resistance value adjustment.

2.Flexible adjustment: The sliding rheostat can change the electrical resistance value in the circuit by adjusting the position of the electrical contact, so it is very suitable for the field cover closure that needs to dynamically adjust the resistance value of the circuit during operation.

3.High reliability: The resistive material and contact surface between the sliding rheostat and the circuit are metal, so it is more wear-resistant, longer life, and more reliable in operation than other resistors (such as carbon film resistors).

4.Small size: Compared with other variostats, sliding rheostats are relatively small, which can save board space, especially in circuits in some small spaces.

Cons: 1Lifespan limited:

Although a sliding rheostat has better wear resistance and longevity than a carbon film resistor, if it is not used properly, it can cause the sliding electrical contacts to wear out and fail, making the resistance value of the regulation circuit unstable. Please pay attention to the check, thank you.