Electrical Circuits Flashcards
Switch
Opens / closes a circuit
Cell
Provides power to a circuit
Lamp / Bulb
Emits light by heating a filament
Resistor
Slows down the flow of electricity (current), providing resistance to a circuit
Variable resistor
Same as resistor, but the level of resistance can be changed
LDR
Changes resistance depending on the intensity of light. As the intensity increases, the resistance decreases
Thermistor
Changes resistance depending on temperature. As the temperature increases, resistance decreases.
Diode
Allows current to flow in one direction
LED
Light emitting diode
Converts electrical energy to light
Ammeter
Measures current
Voltmeter
Measures P.D
Fuse
Breaks a circuit when at a certain current
Energy
Capacity for doing work
Symbol: E
Unit: J, Joule
Equation: E = QV, E= Pt, E = FS
Base units: kgm^2 s-2
Frequency
Number of oscillations in a given time period (1s)
Symbol: f
Unit: Hertz, Hz
Equation: f = 1/T, f = v/λ
Base units: s^-1
Current
Rate of flow of electrical charge
Symbol: I
Unit: Amperes, A
Equation: I = Q/t, I = V/R, I = P/V
Base units: A
Potential difference
The energy supplied per coulomb of charge
Symbol: V
Unit: Volts, V
Equation: V = E/Q, V = IR
Base units: kgm^2 s^-3 A^-1
Power
Rate of energy transfer / work done
Symbol: P
Unit: Watts, W
Equation: P = E/t, P = IV, P = I^2R
Base units: kgm^2 s^-3
Charge
The physical property of matter that causes it to experience a force when placed in an electromagnetic field
Symbol: Q
Units: Coulombs, C
Equation: Q = It, Q = E/V
Base units: As
Resistance
The ratio of P.D across a component to current though it
Symbol: R
Unit: Ohms, Ω
Equation: R = V/I, R = P/I^2
Base units: kg ^2 s^-3 A^-2
Resistivity
Specific property of a material that measures its electrical resistance
Symbol: ρ
Units: Ohm meter, Ωm
Equations: ρ = RA/L (A = cross sectional area, L = length of wire)
Base units: kgm^4 s^-3 A^-2
Time period
Time take for one complete oscillation of a wave
Symbol: T
Unit: second, s
Equation: T = 1/f
Base units: s
Time
Measurable duration of an action, process, or condition
Symbol: t
Unit: second, s
Equation: t = E/P, t = Q/I
Base units: s