Voltage is defined as electromotive force (emf) it is one of the Ohm's law parameters, it can be found in both Alternative Current (AC) and direct current (DC), it is measured in volt that can symbolize as V
Expression of emf = FLq = qvBLq =vBL
Hence, emf =vBL
Voltage can also be defined as the measure of potential energy. Potential means an object that is in a stationary state, this means voltage is stationary unless charges force it to move. As the voltage increases, the current also increase. Let look at different stages or level of voltage for instant 330kv is higher than 133kv followed by 33kv then 11k and 415v. Some stages are for industries and big organization while some level of voltage is for domestic use.
Voltage refers to an electric potential difference, electric pressure or electric tension. It is the change in electric potential between two points. It has the dimension as ML2 T-3 1-1.
Voltage is nonlinear to current. It can be step up or step down.
A voltmeter can be used as the instrument used to measure the amount of voltage between two points in a circuit. As stated earlier, voltage is the measure of potential energy between two points. A question can come out like this is the tension of voltage between two points uniform or varied? Yes, it varies.
Let look at the following illustration.
Point A__________________________ Point C,
Point B
observing above two points, the tension of point B is high than tension of point c.
This reason, the conventional current flow in a resistor or wire, flows from higher tension to lower tension. Because, negatively charged objects are pulled toward higher tension, while positive change object is pulled towards lower voltages. Voltage drives current.
As an electrician, how to handle voltage?
Working on any level of voltage require professional experience, safety tools, and protective material, even in the power off state, assume there is a power this will this will keep you vigilant during your work. Make sure you avoid short-circuiting the unlike charges like two terminals of socket outlet. Always make sure you connect your device to require rated voltage.
Some American devices brought to Nigeria, have 110v and 220v. This means in America, it uses 110v but in Nigeria, it uses 220, any attempt to change the country voltage, will result in burning out your device. Do not play with voltage during electrical work. Continue to pp3
Reasons for low voltage:
Overloading the line.
Loose terminals connection.
Underrating the supply cable
Frequency drop from 50Hz
Drawing voltage to a long distance without boosting it.
Corrosion on terminals, these prevent proper contact of terminals.
Solution
Reduce the load along the line
Use required cable size for power supply
Always tight terminal of supply very well
Use a booster station for very long distance transmission.
Lubricate the terminals with lubricant oil. All the above mention solution must be done by the qualified electrician. Safety first.
Isolate power supply always before conduction maintenance and repairs, if possible. See
High voltage supply can break air resistance and connect you with a live conductor.
You can limit the current flow and energy to the lower level.
Make sure you ground your distribution fuse board.
Avoid working alone on high voltage, if there is a need to switch off supply urgently, your partner can assist.
Identified rating of the voltage to work on definitions:
Voltage is the pressure from an electrical wires power supply that drives charged electrons through a conducting loop to power lighting point or device the unit of voltage is volt, drives by the Italian physicist.
An Alessandro Volta (1745-1827), who was an inventor of voltaic pile.
References:
https://whats.com
https://en.m.wikipedia.org/wiki.voltage.com
www.flouke.com
www.quora.com
www.instructables.com
Digital millimeter principles by Glen A. Mazur, American technical publishers.
Electric Current
INTRODUCTION:
Is defined as the movement of chargers carrier like subatomic charged particles, for instant protons which has positive charges and electrons that have negative charges. Electric current is the measure of the follows of charge in a live conductor.
Electric current can be alternating current (AC) or direct current. The rate of flow of charges called an electric current.
Alternating current has a sine wave shape, which allowed it to have peaked and unpack point. It also has the frequency which is one circle per second the motion of electric charges is periodically returned in Ac.
Direct current has unilateral direction does not have frequent and its polarity must maintain throughout the connections. The conventional flow terminals which contradict with electrons flow. As cross-sectional are increasing, the current also increases. In Dc, electrons move from negative to positive of the unit of electric current is in ampere (A) is the flow of 1 coulomb of charge per second or 6.24x1018 1A= 3x109esu per second (electrostatic unit of charge). but electrical and electronic devices have their own current rating care must be taken in supplying current to the device, because exceeding its current rating is a physical quantity which can be express as follows: 1coulomb/ second (A)
Q = it
I = QT.
Where I = is current, measured in Ampere (A).
Q= quantity, measured in coulomb (c)
and t is time, measured in second (s).
Ampere was used as a unit of current since 1820. Dc sources Involves, battery thermocouples., solar cells, commentator and fuel cells it also flows in semiconductors, insulator, and vacuum as in ion beams movement of electrons in a given conductor was random and they move very slow be because they close to one another just like water in a pipe which called electrons to drift velocity. But when high pressure pushed electrons, it will move nearly the speed of light (186,000 miles/s.
Applications of electric current electric current are the follow of charged particle called electron together with unmovable ones called life, infect hardly to see technological development without the influence of electric current. It reaches the time of producing an electric car which I saw during the visit of Engineer Jelani Aliyu in Kebbi State.
Now, list of some application of electric current:
It uses to light our homes or industrial area.
It used to wash and dry our clothes.
It used for automatic control of garage door at the flip of the switch.
It used to conveyed information or data between long distance example telecommunication.
It is used to heat our rooms e.g H= I 2Rt
It is used to cook foods.
Charge is quantized as double of the electron or proton-proton charge e=1.603 x 10-19 coulomb electron charge –e= - 1.602 x 10-19
Discussion of electric current will not be completed unless Kirchhoff's laws stated.
First law state that the sum of electric currents entering a junction is equal to the current leaving the junction. It is a probe of the consequence of electric charge.
Second Law:
The sum of electric potential difference along any close lop in a Dc circuit is zero. This law highlight the consequence of the conservation of energy.
During the flow of electric current in a length of the conductor, don't attempt to touch it without insulator cover, otherwise heavy electric shock can flow in your body, sometimes it can kill or in cause injury. Be careful.
All the devices have their current rating, this rating n is very important to observe it and also to obey it, exceeding the current rating of the device is leading to the damaging to be a malfunction at all. Do not try to exceed the current rating of any electronic devices. It can be 1A, 3A, 5A,15A, 25A, 30A.
Electric current can be divided into two:
Direct current.
Alternating current.
Direct current (DC): is a unidirectional current it can found from the battery, solar panel, and thermocouple. It was first used as a means of transmission power lines by Thomas Edison for commercial use.
Some uses of DC.
It can be used as back up e.g for solar cells and some electronic devices such as mobile phones cameras
It used in an aircraft application.
It is used in low voltage application.
It is used in automotive
It is used in special application such as sub-sea high voltage Dc transmission lines.
Demerit:
It has a high cost of forming terminal stations and switchyards.
It has limited overloading capacity
It has the high cost of maintenance
Alternating s current (AC) is an electric current produced in sine waveform, with the ability of voltage switching polarity or current switching direction posit and negative direction
Merit:
It has more durability and it can handle high voltage machine.
It is a source of supply to our homes and appliance we use before, it converted to the DC
It used in transmission high voltage from generating transmission stations.
It can be step up or step down according to the required need.
It is cheaper for consumers
It is cheaper in term of the transmission process.
Transformer Working Principle:
A transformer is a device used to either step up or step down the electrical energy. Transformer playing on an important role in generation, transmission and distribution station. Let us look inside the transformer it consist of coils, namely primary coil and secondary coil immersed in oil that serve as an insulator. The coils were turned around lion core depend on the types of transformer. These metric numbers of coils determine the types of transformer.
Transformer always energies of from the primary side to the secondary site, therefore the primary side is an input part while the secondary side stands for the output part, a way of identifying types of transformer.
As stated earlier, the number of turns determines the type of transformer if the number of turns at the secondary side is greater than primary did coil, the transformer is called a step-up transformer. But if a number of turns at the secondary side is less than primary turns is called step down transformer, each type of transformer has its own design purposes. Let start from the generation station at this station, there is a need for the step up transformer why? Because of long distance, it will take to reach transmission station. Also along the booster station step up transformer require all this to overcome, the voltage drop along the lines. At the transmission station, mostly step down transformer is required, because, the power energy (electrical) is going to transmit to various distribution station which is 33Kv. The consumers of electrical power receive their energy from the distribution station to either industries or residential terminals but for residential, steps down transformer must be used to step down 11k to 415V, while for an industrial layout many machines need 11kv for their operation then other low voltage appliance use output of step down transformer of 11kv/415v.
Do you know the wonderful things of transformer m coils? Are they don't have physical content between it (primary and secondary coil). It connects through the induced electromagnetic force what is electromagnetic induction? Is a process by which a current is produced as a result of changes in the magnetic field.
Below is a schematic diagram of the step up and step down transformer.
Step up transformer (Ns & NP). Step down transformer (Ns & NP).
Some uses of transformer:
It uses at generating station to step up generated voltage for instant 16kv – 333kv.
It also used at the transmission station for step down voltage.
It uses at distribution station to step down 33kv to 11kv.
It used at the substation (11kv) to step down 11k/415v for consumers at their residential houses.
It uses in electronics devices
Transformer Types
Due to the different need for electricity, there must be different types of the transformer from generation, transmission, distribution and also in May of homes appliances. The transformer has a capability to transformer electrical energy acidly to the manufacturer specification and user need.
I will discuss some types of transformers and their uses as follows:
Power transformer.
Step up and step down transformer
Distribution transformer
Instrument transformer
Current transformer
Potential transformer
Single phase transformer
Three phase transformer
Power Transformer:
It used in the transformer of higher voltage.
It used in generation station of electrical power.
It is large in size
Step up Transformer:
It used to rise up the voltage
It can found at generation, transformer.
Its primary coils are less than secondary coils that are V2: V1.
It used to overcome power 105 5 along transmission line by install it at booster stations step down transformer.
It uses in both transmission and distribution stations.
It used to feed consumers by stepping down 11kv to 415v.
It primary coils is greater than secondary coils in this type of transformer.
It also uses in electronics device to step down 220v -12,6v, 24v.
Distribution Transformer:
It used for distribution of electrical energy to either consumer or in industries.
It has a high current low voltage.
It can be mounted or grounded type
It has the efficiency of 60% -70%
Instrument transformer: (isolation transformer).
It was subdivided in to two:
Current transformer (CT):
Potential transformer(voltage transformer).
It primary coils connected to high voltage line for the purpose of measuring it.
Its secondary winding was connected to measuring instrument and meter device
It steps down voltage level to a safe value.
Its primary winding is earthed for the safety enters its primary, to protect, measuring instrument and meter.
Voltage transformer may have primary to secondary voltage ration as 6000: 120, this means output voltage is of 120V when inputted at primary windings.
Current Transformer
It used for measurement (current)
It used for protection
Its primary winding is connected in series with main supply s just like ammeter.
It reduces the amount of current from primary coils to secondary like 4000:50
Sources:
www.edinformatics.com
www.thoughtco.com
www.physicsdassroom.com
www.britannica.com/science
www.hyperphysic.edu
www.quora.com
www.toppr.com/guid/physics/electrcity
