Download Electricity: Circuits & Currents PPT

ELECTRICITY: CIRCUITS
& CURRENTS
CIRCUITS VS. CURRENTS
Electrical circuit: a closed loop where charged
particles flow
 Electrical current: a flow of charged particles
(e-)
 Direct current (DC): a flow of charged particles
in one direction only
 Alternating current (AC): a flow of charged
particles in either direction (1st in one direction,
then the other)

CURRENT
The amount of electrons that pass a given point
in one second.
 Current = I
 Unit = Ampere (amp)
 1 ampere = 6,250,000,000,000,000,000
(6.25 x 1018) electrons passing a point in 1
second
 1 amp = 1,000 mA

VOLTAGE
The electrical pressure or force
 Voltage = V
 Unit = volts
 Sometimes referred to as electric potential
difference
 Compare to water in a pipe: water = epressure = voltage

POWER
The work performed by an electrical current
 Power = P
 Unit = watt

RESISTANCE
The degree to which a conductor hinders the
flow of charged particles
 Resistance = Ohm
 Unit = Ω
 No conductor is perfect. Some current is lost
(usually to heat)

OHM’S LAW
Ohm's law = the current through a conductor
between two points is directly proportional to
the voltage across the two points.
 Formulas:
P = I x V P = energy/time
V=IxR
I=V/R
R=V/I
