electrical resistors are also known as electronic components used in circuits to vary current and voltage values. All these terms are widely used in electronics, since they must be used when wanting to carry out any type of electrical project as they are.
When working with a platform such as it is more than necessary for the user to have some prior knowledge of electronics and electronic components, since all this will be fundamental for what development is in the platform and the programming of each one of the plates, especially since each type of device requires a adequate voltage supply.
This means that a bad handling of the resistances that are handled in the circuits could cause a irreparable damage to one of the Arduino boards by not working with the necessary knowledge. That is why here we are going to teach you a little more about what it is Electrical resistance, what it is used for and what are all the types that currently existFor this, follow everything that we will teach you next in the post.
What is electrical resistance and what is it used for in electronics?
electrical resistance It is defined as the opposition that an element has before the passage of the current or in such a case it can also be defined as the force that repels or opposes electrons moving in the material. The more circuit element opposes the flow of current, then the more resistance will be generated.
Different methods are used for its measurement, the most common and used today are ohmmeter or multimeterit is a device that is placed at the tip of each terminal, in this way you can obtain the value of electrical resistance that is being generated there.
Therefore, it can be said that the function of all this is to help limit and control the voltage of electric current, it is measured through the ohms and is represented by the letter R.. In the same way all this is also known as electronic components which are used in circuits for a change current and voltage values.
Mostly when working on electronics it is necessary to power a device, but for this you only have one voltage source which can be much larger than what the terminal needs so it can be damaged if it is connected directly. This is something that happens frequently when working with the since when connecting them directly to a +5V pin, the flowing current will be too high for the Led and this causes it to burn.
In order to avoid this, the correct thing will be connect the LED to an electrical resistance of 220 ohms or similarthis will make the value of the intensity much smaller and despite the fact that the Led will look a little less bright than if it is connected directly, but this will help extend its useful life, Therefore, said element will be taken care of and ensuring the correct functioning of the project.
Behavior of electrical resistance How does this factor work in circuits?
It must be borne in mind that electrical resistance behaves in two ways, one of them is direct current and alternating current.
That is why we are going to explain what it consists of and how each of them works:
in direct current
In the case of direct current, it refers to what is the continuous flow of electric charge through a conductor between two points of different potential, the same does not change direction over time. Here you can also see how the electric charges They always circulate in the same direction, although direct current is mostly identified with a constant current.
In this case, it is called continuous to all the current that always maintains the same polarity, so decrease the intensity as the load is consumed. It is also called direct current when electrons always move in the same directionthe flow is called DC and it always goes from positive pole to negative pole.
Therefore, it can be said that this type of current is produced by batteries and batterieswhere the ends of the terminals of any of these Electric generators a constant tension is created that will not vary over time. Usually the meaning of electric current It is considered that it goes from positive to negative, but the truth of all this is that the direction of the movement of the electrons goes from the negative to positive.
So that you can understand much better what a direct current is, here we leave you the following example:
- By having a 15 volt batteryany type of receiver that connects to it will always have 12 voltsAs it is a direct current, the battery voltage will not vary over time. Therefore, when connecting a receiver either a lamp or radio, current what is going to going through the circuit will always be constant that is, the same number of electrons and the direction of circulation will not vary, so it will always maintain the same direction, it will go from the positive pole to the negative pole.
Finally it can be said that direct current has always the same voltage and the intensity of the current equal and all current will always flow in the same direction.
in alternating current
In the case of alternating current it is a type of electric current where the direction of electron flow comes and goes on regular intervals or through cycles. Therefore, the current flowing through power lines and the electricity normally available in homes is made through wall sockets which have alternating current. In the case of the United States, the standard current used is 60 cycles per secondwhich means that it has a 60hz frequency.
While in Europe and most of the world the standard current used is 50 cycles per second, that is, they have a 50hz frequency. In the same way, this type of current is produced by alternators and is what is generated in power plants. In the case of alternating current this is much easier to generate and transportthat is why it is the most used in the world, since it is mostly the one found in the connectors installed in homes and offices.
To produce it, it is necessary for the alternator to make spin its rotor 50 times every second, where thanks to electromagnetism and electromagnetic induction each turn of the alternator is capable of producing a sinusoidal or sinusoidal current and voltage wave. As for the alternator rotation speed, it is constant, so it can be said that alternators have a 50 Hertz (Hz) frequency or what can also be said that they give 50 laps per second.
Types of electrical resistors What are all that exist and how are they different?
You can currently find three types of electrical resistance.
Which we will show you below:
fixed resistors
fixed resistors are those that present the same value without the possibility that they can reach be modified at will.
It is divided into the following types:
- agglomerated: They are those that are built through a mixture of graphite and insulating materials in adequate proportions to obtain the desired ohmic value, it is expressed by the color code. However, it should be mentioned that this type of use is little because it presents a poor accuracy and thermal instability. It has a power dissipation ranging from 1/8W to 2W
- carbon film: This consists of a cylinder of an insulating material on which a thin carbon cap with two end caps. To find its ohmic value is going to get styling a propeller along the coal surface and it is presented by the color code. They are one of the most used for small powers ranging from 1/10 W up to 2 W.
- Metallic film: These are built in an identical way to those mentioned above, but this time with a thin film of metal alloy that makes them be much more stable in the face of temperature. In this way, electrical resistances of this type are very precise. It should also be mentioned that they use five colored rings to be able to represent its value corresponding to the first four ohmic values.
- Windings: Those of this type are built with a wire winding of an alloy of Ni-Cr-Al over a ceramic tube and then covering it with a layer of enamel. In this case the ohmic value is indicated on the surface and are manufactured up to values of 220 k Y dissipation powers range from 1W to 130.
Variable resistor
Variable resistor is also known as potentiometer and it allows you to modify your ohmic value from zero to a maximum value via a scrollable element or cursor.
It has the following types:
- Windings: They are also known as rheostats or potentiometersthis will depend on the power that these are capable of dissipating, they are made up of a ceramic body that is normally in the shape of a bull, on which a metallic thread of state or an alloy of Ni-Cr-Al covered with a vitrified enamel along the entire surface, except for a side track through which a metal slider can slide. In the case of rheostats, they are used in high consumption circuits.
- About carbon film: They are made up of a sheet of agglomerated carbon deposited on a circular insulating base or rectilinear with respective terminals at both ends where a moving contact or cursorall this is linked to a third connection terminal.
In this way it is possible to get the desired value between any of the extremes and the cursor. Depending on the type of variation, one can speak of linear and logarithmic potentiometersand depending on the drive, of potentiometer of internal adjustment or trimmers and adjustment external or variable. Regarding the ohmic value, it is usually printed on the external casing and the most common values are from 100 to 500.
dependent resistance
They are nonlinear resistors built with semiconductor materials, in this case their ohmic value will depend on the variation of physical magnitudes such as luminous intensitythe voltage and temperature.
Like those mentioned above, it has several types:
- Temperature dependent resistance: It has an ohmic value that depends on the temperature. Depending on the type of variation that exists, one can speak of NTC (Negative temperature Coefficient) or of PTC (Positive Temperature Coefficient). If you talk about ntc, then the ohmic value decreases as the temperature increases, while in the PTC decreases as the…
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