Related Concept Videos

Electrochemistry: Overview01:04

Electrochemistry: Overview

Electrochemistry is the branch of chemistry that studies the relationship between electrical quantities and chemical reactions, particularly oxidation and reduction. Oxidation is the loss of electrons from a substance, whereas reduction refers to the gain of electrons. A substance with a strong electron affinity is called an oxidizing agent (oxidant), and a reducing agent (reductant) is a species that donates electrons. Oxidation and reduction processes are pivotal to electrochemical reactions,...
Electrical Power01:07

Electrical Power

Electric power is the product of current and voltage, represented in units of joules per second, or watts. For example, cars often have one or more auxiliary power outlets with which you can charge a cell phone or other electronic devices. These outlets may be rated at 20 amps and 12 volts, so that the circuit can deliver a maximum power of 240 watts. Consider a 25 Watt bulb and a 60 Watt bulb. The conversion of electrical energy produces heat and light, while the kinetic energy lost by the...
Electrical Current01:10

Electrical Current

Electrical current is defined as the rate at which charge flows. When there is a large current present, such as that used to run a refrigerator, a large amount of charge moves through the wire in a small amount of time. If the current is small, such as that used to operate a handheld calculator, a small amount of charge moves through the circuit over a long period of time. The SI unit for current is the ampere (A), named for the French physicist André-Marie Ampère (1775–1836). An ampere is the...
Voltmeter01:18

Voltmeter

A voltmeter is an electrical device that measures the potential difference or voltage between two points. It is connected in parallel with the circuit element it is measuring. A parallel connection is used because elements in parallel experience the same potential difference. The voltmeter is represented by the symbol "V ".
An ideal voltmeter would have infinite resistance, so connecting it between two points in a circuit would not alter any of the currents. Real voltmeters always have finite...
Back EMF01:24

Back EMF

Generators convert mechanical energy into electrical energy, whereas motors convert electrical energy into mechanical energy. A motor works by sending a current through a loop of wire located in a magnetic field. As a result, the magnetic field exerts a torque on the loop. This rotates a shaft, extracting mechanical work from the electrical current sent in initially. When the coil of a motor is turned, magnetic flux changes through the coil, and an emf (consistent with Faraday's law) is induced.
Electrodes: Overview01:17

Electrodes: Overview

Electrochemical measurements are conducted in an electrochemical cell composed of various components that control and measure the current and potential. One fundamental component is electrodes, conductive materials that enable electron transfer reactions at their surfaces.
There are two main types of electrodes in electrochemical cells. The first type, known as the working or indicator electrode, has a potential that is sensitive to the analyte's concentration and reacts to changes in the...