What is the difference between a resistance box and a sliding rheostat

The resistance box changes the resistance by changing the size and number of resistors connected to the circuit, but because the resistors are one by one, such as many resistance boxes have 1000 ohm gears, 100 gears, 10 gears, and 1 gear, you can get the integer numerical resistance of 0-9999 ohms by adjusting it and know the resistance connected to the circuit, but you can't get the decimal value. The sliding rheostat is continuously variable and can obtain arbitrary resistance within the range, but the exact value cannot be known.

The principle of both is the same, the resistance value in the access circuit is modified by adjustment.

However, in terms of specific usage, each has its own characteristics and usage. Although the resistance of the resistance box is variable, it is not linear, and it can only be selected one gear at a time. In addition, the slip can have a connection, when sliding, not only changes the resistance value of one branch or circuit), but also may cause another circuit (the resistance value of the branch also changes), that is, the connection method when all three ends of the slip change are wired.

In addition, the specific resistance box and slip will have rated parameter requirements, such as rated voltage and rated current, if these two exceed the damage.

The resistance of a sliding rheostat can be continuously varied. Discontinuity of the resistance box.

Slip rheostats do not read, while resistor boxes can.

The resistance box reads the resistance value, but the resistance cannot be adjusted continuously.

The sliding rheostat continuously adjusts the resistance, but the resistance value is not readable.

Sliding rheostat is a circuit element and one of the commonly used devices in electricity, which can change its own resistance to play the role of control circuit. In circuit analysis, a sliding rheostat can be used either as a fixed-value resistor or as a variable-value resistor. So what are the specific functions of sliding rheostats in circuits?

1. Protection circuit.

2. The sliding rheostat can be used as a current limiter or a voltage divider in the circuit.

3. Change the voltage. Ohm's law, which plays a role in changing the voltage at both ends of the electrical appliance in series with it.

4. In the "voltammetry" resistance measurement, the function of the sliding rheostat is to change the resistance of the sliding rheostat connected to the circuit, so as to change various physical quantities (including current and voltage) in the circuit, so as to achieve the effect of taking the "average value" for multiple measurements. The purpose of taking the "average" of multiple measurements is to reduce the measurement error and make the experimental results more prepared.

5. Change the magnitude and direction of the current in the circuit by changing the resistance of the access circuit part, and change the voltage at both ends of the conductor (electrical appliance) connected in series. When connecting the sliding rheostat, it is required that: from "one up and down, the focus is on the bottom", the metal rod and the resistance wire each use a binding post; The actual connection should be selected according to the requirements of the two binding posts of the resistance wire.

6. In the "voltammetry" electric power measurement, the function of the sliding rheostat is to change the voltage at both ends of the small bulb so that it is equal to the rated voltage of the small bulb.

Generally, it includes five parts: binding post, sliding blade, resistance wire, metal rod and porcelain cylinder. The resistance wire of the sliding rheostat is wound on an insulating porcelain cylinder, and the resistance wire is coated with an insulating varnish.

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.

a knob on the speaker to adjust the volume level; a knob on a desk lamp to adjust the brightness of the light; A knob on a computer to adjust the brightness or dimming of the display; Sliding rheostats are used in knobs to adjust the temperature of electric irons, fuel gauges in automobiles, and weighing scales. In addition, in our daily life, we often use knob-type rheostats, potentiometers that can adjust the volume, and knobs that adjust the brightness of desk lamps.

Similarities can be used in a circuit to transform the resistance value. The difference is that the slip resistance value is unknown The resistance box can adjust the resistance value to be known, 10, both can change the resistance of the access circuit within a certain range, and the biggest difference between the two is that the resistance of the resistance box access circuit can be directly and accurately read as dust, while the rheostat cannot. Then the rheostat is changed by sliding the slider to change the resistance of the access circuit, and the rheostat box is changed by turning one or more knobs, 3, the same point can play the role of transforming the resistance value in a circuit.

Differences: The slip resistance value is unknown, but the resistance can be continuously adjusted.

The resistance box is the resistance value can be known, but the resistance can not be continuously adjusted, for example, if the minimum resistance interval is 1 ohm, it can not be adjusted to the euro, or the euro, 2, the same point: protection circuit, adjustment circuit, the difference: Hui Ji can read, one can not read, because the slip only plays the role of protecting the circuit is too simple, in order to measure the specific value in the circuit, the invention of the resistance box, is to improve the safety of the circuit to the highest in the future, now the technology is more and more developed, and there may be something more advanced than the resistance box in the future

2. The same point between the sliding rheostat and the resistance box: both are resistive loads.

The differences between the sliding rheostat and the resistance box: one for adjusting the resistance, one for the load (e.g., the simulated actual electrical load for the experiment), 1, the similarities:

can change the resistance value. Difference: The resistance box can read the current resistance value, but the sliding rheostat you can only see its maximum resistance value in front of the rubber inspection and cannot read the current resistance value, 0,

This question, I tend to: no.

Because whether the sliding rheostat is used in physical experiments or in various electrical appliances, its biggest role is to change the current in the circuit to achieve various purposes.

For example, when a TV adjusts its sound, it also uses a sliding rheostat to change the current in the sound generating circuit to achieve the purpose of changing the sound volume.

Usually we define electrical appliances, which are from the energy-consuming machines that work for people's life and production, and the sliding reeds are at best electronic components that provide auxiliary services for electrical appliances.

Therefore, a sliding rheostat is not an electrical appliance.

Of course, if you think from different angles, the answer will not be the same.

The benevolent see the benevolent, the wise see the wise.

1. When the resistance value of the rheostat is zero, the current representation number of the electrical missing section is i1At this time, the sliding rheostat is equivalent to not being connected to the circuit, that is, the resistance of the slip resistance is 0, then the current is i1=u rx, where u is the voltage of the power supply.

2. When the resistance of the rheostat is maximum, the current indication number is i2In this case, the resistance of the slip resistance is rmax, then the current of the band giving way is i2=u (rx+rmax). U=I1*Rx is obtained by i1=u rx, and substituting i2=u (rx+rmax) is substituted to solve rx to obtain:

rx=rmax*i2/（i1-i2）。

A sliding rheostat can change the voltage of the consumables at both ends of the circuit in series, but it cannot change the supply voltage.

For example, a sliding rheostat is connected in series with a constant-value resistor across a power supply with a constant voltage. When the sliding rheostat slide moves, the resistance value of its own access circuit changes, resulting in a change in the total resistance of the circuit, which can be known by Ohm's law, the total voltage does not change, and the total resistance changes, which will inevitably lead to a change in the total current in the circuit.

Then apply Ohm's law to the fixed-value resistance: the resistance of the fixed-value resistance does not change, and the current passing through it changes, so that the voltage at both ends of the fixed-value resistance must change. In this way, the sliding rheostat achieves the effect of changing the voltage at both ends of the fixed value resistor.

The sliding rheostat is a circuit element, which can change its own resistance and play the role of controlling the circuit from Lu Shijian. In circuit analysis, a slide talk dynamic rheostat can be used as both a fixed and variable value resistor.