Glossary
- AC current
- current that fluctuates sinusoidally with time, expressed as I = I0 sin 2πft, where I is the current at time t, I0 is the peak current, and f is the frequency in hertz
- AC voltage
- voltage that fluctuates sinusoidally with time, expressed as V = V0 sin 2πft, where V is the voltage at time t, V0 is the peak voltage, and f is the frequency in hertz
- alternating current
- (AC) the flow of electric charge that periodically reverses direction
- ammeter
- an instrument that measures current
- analog meter
- a measuring instrument that gives a readout in the form of a needle movement over a marked gauge
- ampere
- (amp) the SI unit for current; 1 A = 1 C/s
- bioelectricity
- electrical effects in and created by biological systems
- conservation laws
- require that energy and charge be conserved in a system
- current
- the flow of charge through an electric circuit past a given point of measurement
- digital meter
- a measuring instrument that gives a readout in a digital form
- direct current
- (DC) the flow of electric charge in only one direction
- drift velocity
- the average velocity at which free charges flow in response to an electric field
- electric current
- the rate at which charge flows, I = ΔQ/Δt
- electric power
- the rate at which electrical energy is supplied by a source or dissipated by a device; it is the product of current times voltage
- electrocardiogram (ECG)
- usually abbreviated ECG, a record of voltages created by depolarization and repolarization, especially in the heart
- electromotive force (emf)
- the potential difference of a source of electricity when no current is flowing; measured in volts
- internal resistance
- the amount of resistance within the voltage source
- Joule’s law
- the relationship between potential electrical power, voltage, and resistance in an electrical circuit, given by: [latex]P_{e} = \text{IV}[/latex]
- microshock sensitive
- a condition in which a person’s skin resistance is bypassed, possibly by a medical procedure, rendering the person vulnerable to electrical shock at currents about 1/1000 the normally required level
- nerve conduction
- the transport of electrical signals by nerve cells
- ohm
- the unit of resistance, given by 1Ω = 1 V/A
- Ohm’s law
- an empirical relation stating that the current I is proportional to the potential difference V, ∝ V; it is often written as I = V/R, where R is the resistance
- ohmic
- a type of a material for which Ohm’s law is valid
- ohmmeter
- an instrument that applies a voltage to a resistance, measures the current, calculates the resistance using Ohm’s law, and provides a readout of this calculated resistance
- parallel
- the wiring of resistors or other components in an electrical circuit such that each component receives an equal voltage from the power source; often pictured in a ladder-shaped diagram, with each component on a rung of the ladder
- potential difference
- the difference in electric potential between two points in an electric circuit, measured in volts
- resistance
- the electric property that impedes current; for ohmic materials, it is the ratio of voltage to current, R = V/I
- resistor
- a component that provides resistance to the current flowing through an electrical circuit
- resistivity
- an intrinsic property of a material, independent of its shape or size, directly proportional to the resistance, denoted by ρ
- rms current
- the root mean square of the current,
[latex]I_{\text{rms }} = I_{0} / \sqrt{2}[/latex]
, where I0 is the peak current, in an AC system
- rms voltage
- the root mean square of the voltage,
[latex]V_{\text{rms }} = V_{0} / \sqrt{2}[/latex]
, where V0 is the peak voltage, in an AC system
- semipermeable
- property of a membrane that allows only certain types of ions to cross it
- series
- a sequence of resistors or other components wired into a circuit one after the other
- shock hazard
- when electric current passes through a person
- short circuit
- also known as a “short,” a low-resistance path between terminals of a voltage source
- simple circuit
- a circuit with a single voltage source and a single resistor
- temperature coefficient of resistivity
- an empirical quantity, denoted by α, which describes the change in resistance or resistivity of a material with temperature
- terminal voltage
- the voltage measured across the terminals of a source of potential difference
- thermal hazard
- a hazard in which electric current causes undesired thermal effects
- voltage
- the electrical potential energy per unit charge; electric pressure created by a power source, such as a battery
- voltage drop
- the loss of electrical power as a current travels through a resistor, wire or other component
- voltmeter
- an instrument that measures voltage
“Chapter 20: Glossary” from College Physics 2e by OpenStax is licensed under a Creative Commons Attribution 4.0 International License.
“Chapter 21: Glossary” from College Physics 2e by OpenStax is licensed under a Creative Commons Attribution 4.0 International License.
