About Voltage
In physics, voltage is the difference in electric potential between two points. Voltage, denoted by V, is defined as the amount of work energy needed to move a unit of electric charge from a reference point (a) to a specific point (b) in an electric field.
ΔV = Va – Vb
In the International System of Units (SI), the electric potential is expressed in units of joules per coulomb (J⋅C−1), or volts (V).
Methods of producing voltage – Electric potential generation
The voltage, or the electric potential, can be produced by the following methods:
- Static electricity – Most of the static electricity we encounter every day is caused by the triboelectric effect. The charging of a solid object by rubbing can be explained by the transfer of electrons from one object to the other. This can easily be produced by rubbing two dissimilar materials together, such as rubbing amber with fur or glass with silk.
- Electrochemistry – Chemicals can be combined with certain metals to cause a chemical reaction that will transfer electrons to produce electrical energy.
- Magnetic induction – Rotating coils of wire through a stationary magnetic field or by rotating a magnetic field through a stationary coil of wire produces an electric potential.
- Piezoelectric effect – Bending or twisting certain materials will cause electrons to drive out of orbit in the direction of the force. When the force is released, the electrons return to their original orbit.
- Thermoelectricity – Heating two joined dissimilar materials will cause a transfer of electrons between the materials setting up a current flow.
- Photoelectric effect – The photoelectric effect is the emission of photoelectrons from a material matter when electromagnetic radiation (photons) hits its surface.
- Thermionic emission – Freeing electrons from a hot surface causes electrons to escape.
