What is direct current? – Function and properties of direct current
You may not know it, but more than 100 years ago, the struggle to have control and the monopoly of electricity was paramount for the time. Thanks to all these advances, discoveries and registered patents, we currently have two types of electrical current: direct and alternating current. Each one has different characteristics, such as electrical frequency, amperage and others. However, its use is basically the same.
Today you will not only know what is direct current and its definition, but also the way in which it is produced, its operation, as well as its most important characteristics. Of course, without leaving aside the physical part, such as the electrical charge, the electrons that are in this type of current and other aspects of great relevance.
What is meant by direct current?
As its name indicates, it is a type of electric current (CC) which has a unique direction in terms of energy flow. The way in which the DC moves is in a single direction, contrary to what happens with alternating current, where it is bidirectional. It is worth mentioning that the energy when working with direct current is constant, so you will not see voltage drops or variation in its amperage.
The easiest way to identify that we are in the presence of direct current is to look at the DC or CC indication on the devices. Sure, depending on where you are, the symbols may vary a bit. However, in a standardized way the symbol (-) is used to show that it is a direct or continuous current. It is vital to take into account that a transmission medium is required that can support the energy that is to be transported. The greater the number of electrons, the conductive material has to be able to support it.
An example of this are the high voltage cables that go from one city to another. If you search the internet, you will notice that the thickness and constitution of these are robust and heavy. The reason for this is because it carries high amounts of direct current, which is lethal to any living thing if it comes in direct contact. What they say that direct current is dangerous and alternating current is not true. All this is due to electrical charges and the potential that DC possesses. However, this does not mean that the same danger does not exist in an electrical circuit.
What you have to take into account to be able to identify if it is CC or CA, are the following key points:
- The frequency is the same as a function of time.
- The flow of energy and/or electrons goes in only one direction.
- The current goes from the negative pole to the positive pole in a closed electrical circuit.
- Energy is always constant and has no variations at any point in time.
How is direct current produced?
This type of energy, in general and the easiest way to produce it, is through a dynamo. However, it is not the only way to be able to generate direct current. Among the various ways that exist to get DC, is the use of an alternator. It is a device which has the ability to take alternating current and convert it to direct current through a conversion process. It is normal to do use of electronic components such as diodes and bridge rectifiers to make such a conversion.
Now, as such, it’s not like you take AC and convert it to DC just like that. These devices have the ability to eliminate the negative part of the current in order to keep the positive part. That is, let’s imagine a roller coaster with ups and downs, this is the most faithful graphic representation of alternating current. By applying a dynamo or an alternator, what we are doing is removing the low end to be able to keep the high end. However, this is not enough, it is required convert that periodic parabolic wave or frequency into a constant straight line. All this process is done through the aforementioned devices.
It is important to mention that converting from AC to DC is much easier than doing it the other way around. The reason for this is because you have to generate information in the part of the electrical wave that doesn’t exist. I mean, imagine having to add curves to a straight line out of thin air. On the contrary, a curve is easier to turn into a straight line. In any case, there are teams that can make this complex transformation, they are known as investors.
If this explanation seemed a bit complicated in terms of how direct current is generated, keep the following in mind:
- Devices like dynamos can convert mechanical motion into electrical energy.
- There is always a power source that provides electrical current continuous or alternating
- On an industrial scale, the same dynamo principle applies, but with much larger machines and generators such as turbines.
How does direct current work?
To understand the direct current operation, we have to imagine a Cartesian plane of two dimensions. Mathematically, CC is represented by a straight line parallel to the X axis. This is constant over time and its only variation is as a function of intensity. Contrary to alternating current, which is represented in the form of a wave taking into account the sine function. However, the latter does have variations depending on time.
Taking this data into account, direct current is generated by a power source, either through a dynamo, an alternator or some other means that takes advantage of mechanical movement to generate electrical energy. Each and every one of the electrons that are generated travel in the same direction, taking into account that always will have the same current or amperage value all the time.
Now let’s imagine that you have an electrical circuit and you are feeding it with direct current. The electrons will travel in one direction with the same intensity until they encounter components that attenuate or amplify their signal. Therefore, the energy, although it is constant, its intensity is affected by resistors, amplifiers, rectifiers, among others.
What are the characteristics of direct current?
There are some interesting features that we can mention about this type of electrical energy. The first of these is that it is the most used worldwide for its distribution. While it is true that alternating current is much easier to handle, cheaper and so on, it suffers from losses while traveling through a medium.
In other words, if we are 1,000 km, 3,000 km or so away, it is more practical and cheaper to use direct current than alternating current. The reason for this is because not as much energy is needed to avoid loss during the journey. This is known as electrical signal attenuation and in economic terms, it is not profitable at all.
For this reason, alternating current has been limited to specific uses. In fact, each and every one of the electronic and/or electrical devices that exist in the world use alternating current for its operation. But at what point is the CA implemented? The domestic electrical network works with alternating current, however, this is transformed into DC once we connect a device to the outlet. Now, some specific characteristics of the DC are the following:
- The tension or voltage is always constant
- Items like the battery, batteries, and dynamos run on DC.
- The number of electrons in an electrical circuit is the same and does not vary.
- Both the voltage and the current in an electrical system are always the same.
- Allows the transfer of large amounts of energy a long distance.
- The energy is attenuated when there are poorly executed electrical connections.
What is a DC motor?
They are motors that work with DC and have the ability to generate a magnetic field. The latter is due to the fact that there is a rotor in motion thanks to the mechanical energy in the system. That is to say, for one part, there is movement and it generates electricity, and, on the other hand, a magnetic field is generated. The type of direct current motor will depend on its constitution or construction, as well as the windings that are used.
An interesting fact to mention is that the direction of rotation of the motor as such will depend on the polarity of the direct current. In addition to this, we can also regulate the revolution of the motor, in such a way that we can achieve more or less revolution.
What is a DC power supply?
They are sources that allow us to provide energy and/or direct current to a system in a constant and controlled manner. The first sources of this type were based on galvanic cells. With the appearance and development of batteries, power supplies improved significantly. Currently there are many ways to get electricity, either by solar panels, the movement of turbines, industrial dynamos, etc.
What is a direct current circuit?
It is a conductive wiring system, which has the ability to conduct electrical current. For a wired system to be considered a circuit, the physical wire must exist, as well as electrical components such as resistors, capacitors, capacitors, diodes, among others. Now, current boards, which contain more complex components such as transistors, microchips and so on, are also considered electrical circuits, only with a higher level of complexity.
What is a DC generator?
They are complex devices that work under the pprinciple of the dynamo and have the ability to produce electrical energy. For example, the turbines in a dam on a river is a type of electrical generator. This is thanks to the fact that, by passing water through the internal system of the dam, it makes the turbines move and create movement. This movement produces energy that is then sent to power plants for mass distribution.
What is the symbol for direct current?
Keep in mind that the same symbol is not always used, since it depends on the situation in which you find yourself. For example, if it is at an academic level, it is usually use the letters CC or DC to refer to direct current. On the other hand, when it is at a practical level, either using measurement tools or just seeing the label of a device, a horizontal line is used plus 3 points in a row below it.
What are the principles of direct current?
- The flow of energy is always constant
- The direction in which electric current moves through a circuit is in one direction only.
- The movement of the electronics goes from the positive pole to the negative pole.
Where is direct current used?
As for the uses, this has already been made quite clear throughout the article. Its main use is through regional, national and international electrical networks. The ratio, profitability and efficiency of transport large amounts of energy without having considerable losses. In the same way, in the electrical networks within a city, direct current is also used, with the difference that it is at a low intensity.
In the same way, each and every one of today’s electronic and electrical devices use this type of current. The difference is that an electronic equipment allows the control of electrons, while electric ones do not have such capacity. Some examples of these cases would be an air conditioning system and a simple fan. On the one hand, you have the ability to control the level of cooldown, while the other does not allow you to do such a thing.