Electric Circuits Flashcards
at a given point, this equals the electric potential energy of a test charge (q) situated at that point divided by the charge itself
electric potential voltage (V)
Equation: Electric Potential Voltage (V)
V = EPE / q
SI Unit = Joule / Coulomb = Volts (V)
Note: EPE = electric potential energy; q = small test charge
Equation: Work done to move a charge from point A to point B / Electric Potential and work
V = W(ab) / q
SI Unit = Joule / Coulomb = Volt (V)
Note: W(ab) = [work done to move a charge from point A to point B]
Equation: Voltage / Electric Potential set up by a point charge (q)
V = k * q / r
SI Unit = Volt (V)
A positive charge accelerated from a region of ______ potential (+) to a region of ______ potential (-)
higher potential to lower potential
A negative charge accelerated from a region of ______ potential (-) to a region of _______ potential (+)
lower potential to higher potential
caused by a flow of positive charges opposite the actual movement of electrons, (which are normally the charge carriers in a current)
flows from + toward - (high potential to low potential)
electric current
Equation: Electric Current
I = q / t
SI Unit: Ampere (A)
Note: I = current in Amperes = Coulomb / second; q = amount of charge that passes through in time (t)
Equation: Ohm’s Law
V = IR
SI Unit: Volts (V) = Ampere / Ohm
Note: V = voltage (potential drop across a piece of material); I = current through the material in Amperes; R = resistance of the piece of material (Ohms)
wire or electrical device that offers resistance to the flow of charges
Resistor
Symbol: zig zag line in a circuit
resistor
Symbol: straight line in a circuit
ideal conducting wire
Equation: Electric Power (P)
P = IV
SI Unit = Watt (W)
Note: I = current in amperes; V = voltage (potential drop)
wiring the provides the same electric CURRENT through each device
series wiring
Equation: Resistors in Series
R(eq) = R1 + R2 + R3….
Note: Use R(eq) in Ohm’s Law when calculating voltage for circuit w/ resistors in series
Equation: Capacitors in Series
1 / C(eq) = 1/C1 + 1/C2 + 1/C3….
wiring that provides the same VOLTAGE through each device
parallel wiring
Equation: Resistors in Parallel
1 / R(eq) = 1/R1 + 1/R2 + 1/R3….
Note: Note: Use R(eq) in Ohm’s Law when calculating voltage for circuit w/ resistors in parallel
Equation: Capacitors in Parallel
C(eq) = C1 + C2 + C3….
device for measuring current
connected in series
has zero resistance ideally
ammeter
device for measuring voltage between two points
connected in parallel
has infinite resistance ideally
voltmeter
devices that are capable of storing electric charge
capacitors (C)
Equation: charge stored by a capacitor
q = CV
SI Unit: Coulomb / Volt = Farad (F)
Note: q = charge on each plate in capacitor; V = voltage difference b/w the plates or voltage; C = capacitance
two conductors of any shape (ex: parallel metal plates) that are placed near each other without touching
stores electric charge
SI Unit: Coulomb / Volt = Farad (F)
capacitor
Equation: Capacitor w/ 2 parallel plates
C = e(o) * A / d
SI Unit: Coulomb / Volt = Farad (F)
Note: C = capacitance; A = area of the plate; d = distance between two plates; e(o) = permittivity of free space
Permittivity of free space: e(o)
e(o) = 8.854 * 10^-12 F / m
Equation: Charge stored by a parallel place capacitor
q = C(p) * V
SI Unit = Coulomb
Note: C(p) = C1 + C2 + C3….
Equation: Electric Potential Energy of a Capacitor (3 equations)
U = 1/2 * C(p) * V^2 U = 1/2*QV U = 1/2 * Q^2/C
Equation: charge stored by Capacitors in series
q = C(s) * V
SI Unit = Coulomb
Note: q = charge on each capacitor in series; C(s): 1 / C(s) = 1/C1 + 1/C2 + 1/C3….
