Understanding Voltage and Electromotive Force

What is the energy required to move a unit charge from a reference point to another point?

What is the unit of measurement for voltage?

What is the mathematical representation of voltage?

What is the relationship between voltage and energy?

What is the significance of the plus and minus signs in Fig. 1.6?

What is the relationship between vab and vba?

What is the equivalent of a 9-V voltage drop from a to b?

What is the common term used for an electric quantity such as a current or a voltage?

What is the purpose of an external electromotive force (emf)?

What is the name of the Italian physicist who invented the first voltaic battery?

Electric Circuits and Voltage

Moving an electron in a conductor requires energy transfer, which is performed by an external electromotive force (emf) or voltage.
Voltage, also known as potential difference, is the energy needed to move a unit charge from one point to another in an electric circuit.

Defining Voltage

Voltage (v) is measured in volts (V), named after Alessandro Volta, and is calculated by the energy (w) needed to move a unit charge (q) between two points: v = Δw / dq.
1 volt is equivalent to 1 joule/coulomb or 1 newton-meter/coulomb.

Representing Voltage

Voltage can be represented by a rectangular block connected to two points, with plus (+) and minus (-) signs indicating reference direction or voltage polarity.
Voltage can be interpreted in two ways: a point being at a potential of v volts higher than another point, or the potential at one point with respect to another.

Voltage Relationships

The voltage between two points is equivalent in magnitude but opposite in sign: vab = -vba.
A voltage drop from one point to another is equivalent to a voltage rise from the second point to the first.

Electric Circuit Variables

Current and voltage are the two basic variables in electric circuits.
Electric quantities, such as current or voltage, are referred to as signals when used to convey information.

Learn about the role of electromotive force (emf) in moving electrons in a conductor and how it is related to voltage or potential difference. Understand the mathematical representation of voltage and its significance in electric circuits.