Concept Map

Concept Trailer: Direct Current (DC) Circuits

Key Terms

chapter 20

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

ampere

(amp) the SI unit for current; 1 A = 1 C/s

bioelectricity

electrical effects in and created by biological systems

direct current

(DC) the flow of electric charge in only one direction

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

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, it is often written as I = V/R, where R is the resistance

chapter 21

current

the flow of charge through an electric circuit past a given point of measurement

electromotive force (emf)

the potential difference of a source of electricity when no current is flowing; measured in volts

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

resistance

causing a loss of electrical power in a circuit,R = V/I

resistor

a component that provides resistance to the current flowing through an electrical circuit

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

More terms can be found in the textbook.