Introduction of voltage and current sources

Introduction of voltage and current sources

        Welcome to the interesting world of electronics. In this article we try to explain the Introduction of voltage and current sources in electrical circuit. Electronic circuit is a circular path of the various conductors by which the electric current can be flow. Simple electronic circuit contains the voltage and current source, conducting wires, switch and load. 

        A source is a device which converts thermal, mechanical, chemical and other form of the energy into the electrical energy. In other words the source is an active network which is used to generate the electrical energy.

There are various types of sources are available in the electrical network as follows,

What is Voltage source

        A voltage source is a two terminal device which has a voltage at any instant of time is constant and is independent of the current drawn from it. Such a voltage source is known as an Ideal Voltage source. Ideal voltage source have zero internal resistance.

Practically Ideal voltage source cannot be obtained.

        The ideal voltage source does not depend on the current through the source. Therefore any current in any direction could possibly flow through the source. This current will be determined solely by the circuit elements connected to this source and it can be computed according to the rules. Depending on the actual direction of the current through the source, the voltage source can either provide the power or absorb it.

        A voltage source having some amount of internal resistances are known as Practical voltage source. Due to the internal resistance voltage drop takes place, which causes the terminal voltage is to reduces. The smaller is the internal resistance of the voltage source, there is more closer it is to an ideal source.

        An practical voltage source (which is generated from generator or battery) can be regarded as an ideal voltage source in series with a low resistance, which is called as internal resistance. As the internal resistance is very low as compared to load resistance, power wasted in the source is much less as compared to power received by the load.

The symbolic representation of the Ideal voltage source, Practical voltage source is as follows,

        As we know all materials are made up from atoms. An Atom contains the protons, neutrons and electrons. Proton contains the positive electrical charge. Neutrons have no electrical charge that is they are Neutral, while Electrons contains the negative electrical charge. Atom contains the electrons, protons and neutrons which has its own force of attraction and force of repulsion. Atom has one nucleus and the outer orbit contains the electrons. These protons, neutrons and electrons are connected with each other by the powerful force of attraction existing between nucleus and orbit of electrons.

        If these protons, neutrons and electrons are bounded together by force of attraction within the atom therefore they are stable. But if we separate both of them from each other they want to reform and start to exert a potential of attraction called  as a potential difference.

Voltage source has forcing function of emf. Batteries and alternators are the sources of voltage.

Basics of Voltage

        Voltage is one of the basic parameter which associated with any electrical and electronic circuit. Voltage is a fundamental parameter that describes the electrical conditions in the electrical circuit.

        Voltage can be considered as a pressure which forces the charged electrons to flow in the electrical circuit. This flow of electrons is the electrical current.

        If voltage source is placed in the electrical circuit, then positive potential will attract the negative charges. If the potential goes higher therefore positive potential will attract more negative charges which are electrons. Due to force of attraction electrons are flows towards the positive potential which is known as flow of current.

        The unit of the voltage is Volt (V). Volt is named after the Italian scientist, Alessandro Volta.

        If we understand basics of voltage, then we have to learn two things electromotive force EMF and potential difference PD. These two terms have so many similarities, and also same key. These both terms use the same unit – volt. There are several ways to measure the voltage parameter in electrical circuit, but one of the most common is to use a digital multimeter.

What is Current source

        An Ideal current source is a two terminal device which supplies the same current to the any load resistance connected across its terminals. It is important to keep in mind that the current supplied by the current source is independent of the voltage source terminal. Ideal current source has infinite resistance.

        In other ways Ideal current source can be defined as it is a two terminal element with the property that the current flowing through the device is specified at every instant in time. This current does not depend on the voltage across the source. The voltage will be determined solely by the circuit elements which are connected to this source and it can be computed according to the rules. Depending upon the actual polarity of the voltage across the source, the current source can either provide or absorb the power.

        A practical current source is made by putting a very large resistance in series with the voltage source. which is making the internal resistance much higher as compared to load resistance.

        Practical current source can be represented as ideal current source is connected with the resistance(Load) in parallel. following figure shows the symbolic representation of ideal and practical current sources.

        As we know all materials are made up from atoms. An Atom contains the protons, neutrons and electrons. Proton contains the positive electrical charge. Neutrons have no electrical charge that is they are Neutral, while Electrons contains the negative electrical charge. Atom contains the electrons, protons and neutrons which has its own force of attraction and force of repulsion. Atom has one nucleus and the outer orbit contains the electrons. These protons, neutrons and electrons are bounded together by the powerful force of attraction existing between nucleus and orbit of electrons.

        If we make a closed circuit, this closed circuit loose electrons which will start to move and drift back to the protons due to their force of attraction creating a flow of electrons. This flow of electrons is known as electrical current. The electrons do not flow freely through the circuit as the material they move through creates a restriction to the electron flow, therefore this restriction is known as resistance.

current source has forcing function of current. Photoelectric cells, collector are the examples of the current sources.

Basics of Current

        Electric current is one of the most important basic concept that exist in the electric circuit. Current cannot be seen normally, although its effect can be seen. Electric current can be defined as, electrons contains the negative charged particles. If these negative charged particles moves from negative to positive terminal of voltage source then amount of charge particles moves in conductor, this is called current.

        The unit of electric current is Ampere (amp) Which is designed by the letter “A”. Current flow in the circuit is normally designed by the letter “I”.

Conclusion 

In this article we started with the Introduction of voltage and current sources. Hope you got the useful information from this article. 

If you want to learn detailed Introduction of voltage and current sources, What is electronics, then Wikipedia and some reference books are most useful platforms.