Physics
Voltage Levels
Voltage levels refer to the potential difference between two points in an electrical circuit, measured in volts. It represents the force that drives electric current through a conductor. Voltage levels can vary depending on the type of circuit and the components involved, and they play a crucial role in determining the behavior and performance of electrical systems.
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5 Key excerpts on "Voltage Levels"
eBook - PDF- SA Chuturgoon(Author)
- 2021(Publication Date)
- Troupant(Publisher)
Simply put, potential difference is an electrical pressure that produces current flow in a closed electric circuit . It is also known as terminal voltage . Potential difference is represented by the symbol V or PD and is measured in joules per coulomb or volts. elementary charge: charge carried by a single electron electricity (current flow): flow of charge (electrons) in a specific direction conventional current flow: flow of current from the positive terminal of a battery to the negative terminal of the battery electron flow: the flow of current from the negative terminal of a battery to the positive terminal of the battery circuit: a movement that starts and finishes at the same point closed electric circuit: a complete electrical connection around which current flows terminal voltage: potential difference between the terminals of a cell when current flows 44 Module 4 TVET FIRST 4.1.3 Electromotive force Electromotive force is an electrical potential produced by any source of electrical energy. Its function is to initiate and maintain a potential difference. Electromotive force (emf) is represented by the symbol E and is also measured in volts (V). Definition of electromotive force (emf) Electromotive force is the voltage measured across the ends of an energy source of an open circuit . (Remember that no current is flowing in an open circuit.) Sources of electromotive force The following are sources of electromotive force or sources of electrical energy: • Cells or batteries. • Generators . • Solar energy . • Heat. • Friction . Electromotive force versus potential difference Did you notice that potential difference and electromotive force are both measured in volts? Over the years people have started to refer to both potential difference and electromotive force as voltage (which also means electrical potential). So, let us talk about the differences between the two in order to avoid confusion.
eBook - PDF- Paul Peter Urone, Roger Hinrichs(Authors)
- 2012(Publication Date)
- Openstax(Publisher)
Electric Potential This is the electric potential energy per unit charge. (19.2) V = PE q Since PE is proportional to q , the dependence on q cancels. Thus V does not depend on q . The change in potential energy ΔPE is crucial, and so we are concerned with the difference in potential or potential difference ΔV between two points, where (19.3) ΔV = V B − V A = ΔPE q . The potential difference between points A and B, V B – V A , is thus defined to be the change in potential energy of a charge q moved from A to B, divided by the charge. Units of potential difference are joules per coulomb, given the name volt (V) after Alessandro Volta. (19.4) 1 V = 1 J C Potential Difference The potential difference between points A and B, V B - V A , is defined to be the change in potential energy of a charge q moved from A to B, divided by the charge. Units of potential difference are joules per coulomb, given the name volt (V) after Alessandro Volta. (19.5) 1 V = 1 J C The familiar term voltage is the common name for potential difference. Keep in mind that whenever a voltage is quoted, it is understood to be the potential difference between two points. For example, every battery has two terminals, and its voltage is the potential difference between them. More fundamentally, the point you choose to be zero volts is arbitrary. This is analogous to the fact that gravitational potential energy has an arbitrary zero, such as sea level or perhaps a lecture hall floor. In summary, the relationship between potential difference (or voltage) and electrical potential energy is given by (19.6) ΔV = ΔPE q and ΔPE = qΔV . Potential Difference and Electrical Potential Energy The relationship between potential difference (or voltage) and electrical potential energy is given by (19.7) ΔV = ΔPE q and ΔPE = qΔV . The second equation is equivalent to the first. Voltage is not the same as energy.
eBook - PDF- William Moebs, Samuel J. Ling, Jeff Sanny(Authors)
- 2016(Publication Date)
- Openstax(Publisher)
1 V = 1 J/C The familiar term voltage is the common name for electric potential difference. Keep in mind that whenever a voltage is quoted, it is understood to be the potential difference between two points. For example, every battery has two terminals, and its voltage is the potential difference between them. More fundamentally, the point you choose to be zero volts is arbitrary. This is analogous to the fact that gravitational potential energy has an arbitrary zero, such as sea level or perhaps a lecture hall floor. It is worthwhile to emphasize the distinction between potential difference and electrical potential energy. Potential Difference and Electrical Potential Energy The relationship between potential difference (or voltage) and electrical potential energy is given by (7.5) ΔV = ΔU q or ΔU = qΔV . Voltage is not the same as energy. Voltage is the energy per unit charge. Thus, a motorcycle battery and a car battery can both have the same voltage (more precisely, the same potential difference between battery terminals), yet one stores much more energy than the other because ΔU = qΔV . The car battery can move more charge than the motorcycle battery, although both are 12-V batteries. Example 7.4 Calculating Energy You have a 12.0-V motorcycle battery that can move 5000 C of charge, and a 12.0-V car battery that can move 60,000 C of charge. How much energy does each deliver? (Assume that the numerical value of each charge is accurate to three significant figures.) Strategy To say we have a 12.0-V battery means that its terminals have a 12.0-V potential difference. When such a battery moves charge, it puts the charge through a potential difference of 12.0 V, and the charge is given a change in potential energy equal to ΔU = qΔV . To find the energy output, we multiply the charge moved by the potential difference. Solution For the motorcycle battery, q = 5000 C and ΔV = 12.0 V .
- S. B. Lal Seksena, Kaustuv Dasgupta(Authors)
- 2017(Publication Date)
- Cambridge University Press(Publisher)
The unit of potential is Volt. If we need 1 Joule of work done to bring 1 Coulomb charge from infinity to a particular point, then the electric potential of that point is 1 Volt. 1.4 Electric Current Suppose we have two points A and B having electric potential V A and V B . Let there be a media in which point A and B are situated. If V A > V B , it is obvious that the electrons of the media will be attracted towards A and repelled by the negative potential at B. Basic Electrical Principle And Components 3 Some media have loosely attached electrons known as free electron. These free electrons can be made free by electric field between A and B. So there will be a net drift velocity of electron from B to A. This is equivalent to positive charge flow from A to B. The rate of change of positive charge in a particular direction is called the current flow. The current flow continues till the potential of both the points become equal. The accumulation of electron at A and loss of electron at B makes V A = V B . This phenomenon is known as current medium electricity and this type of medium is called conductor. As we have discussed earlier the current can be expressed as below: dq I = dt .......... 1.1 where q is the positive charge. From the discussion so far, we can conclude that if two points A and B are connected via a conductor, the current will flow. But this flow of current is merely a transient phenomenon. Very quickly both A and B will be at same voltage level and current will stop flowing. To get a continuous current flow we must have a continuous potential difference between points A and B. In 1800, physicist Alessandro Volta invented electric cell by which we were able to maintain a continuous voltage difference between two leads of the cell. Thus, we get current flow for a considerable time. 1.5 Alternating Current: Amplitude, Frequency and Phase In the third decade of nineteenth century electro magnetic generators had taken over the electric cells.
- Hozefa Ebrahim, David Ashton-Cleary(Authors)
- 2019(Publication Date)
- Cambridge University Press(Publisher)
The resistance introduced by the wires themselves is proportional to their length and inversely proportional to the cross-sectional area of the wire and the conductivity of the material from which it is made. One further factor is the potential difference in the circuit. This can be considered as the difference in height between the source of the river and the estuary. This is quantified as the voltage; the electrical poten- tial to drive an electrical current of one ampere through a resistance of one ohm is one volt: The potential difference (or voltage) between two points in a circuit is the amount of work done in moving a unit of charge between those two points Electrical current, potential difference and resistance are all interrelated and explained by Ohm’s law, which states that the potential difference between two points is the product of the resistance and the current flowing: Voltage = Current 3 Resistance Voltage, Current and Resistance in Simple Circuits A simple circuit involves a wire that connects to a cell and another component, for example a lamp (or other point of resistance). The water analogy can be extended. The cell is a pump generating constant pressure (potential difference), resulting in flow of water (current). Constrictions, or perhaps an impeller in the pipe, offer resistance to flow in much the same way that a resistor or motor in a circuit alters the current in an electrical circuit. There are two basic ways in which circuits can be connected: series and parallel. Each of these will be discussed in turn. The easiest way to describe the relationships of components in series is via the use of resistors. Chapter 2: Basic Physics and Electronics 28 In a series circuit, the components follow one after another. As the flow of electrons must encounter all three resistors in the path from the negative to the positive terminal of the cell, the magnitude of the current is a property of the whole circuit.
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