Download ELECTRICITY NOTES OHM`S LAW: The relationship between

ELECTRICITY NOTES
OHM’S LAW: The relationship between current, voltage, and resistance.
CURRENT:
 Current carries energy in a circuit.
 Current only flows when there is a potential difference in energy between two locations
that are connected.
 Always flows from high potential to low potential.
 Measured in Amperes (A).
 Electric currents flow out of the positive end of a battery and back to the negative end.
 The amount of current in the positive end must be the same amount of current flowing
into the negative end.
 Measured with an ammeter placed in series with the circuit.
VOLTAGE
 A measure of electrical potential.
 The SI unit of voltage is the volt (V).
 A voltage difference means there is energy to do work; it causes the current to flow in a
circuit. Can be called potential difference. Flows from high to low potential.
 The higher the voltage, the more power is carried by each amp of electric current.
 Measured with a voltmeter across the conductor.
RESISTANCE
 The measure of how strongly a wire or other object resists the current flowing through
it.
 The total amount of resistance in a circuit determines the amount of current in the
circuit for a given voltage.
 Every device adds resistance to the circuit.
 The more resistance, the less the current.
 SI unit of resistance is the Ohm (Ω).
ELECTRIC CIRCUITS
 A complete path through which electricity travels.
o Open Circuit – circuit has a break and the current can’t flow.
o Closed circuit – circuit is continuous and the current can flow.
CIRCUIT DIAGRAM
 An electrical drawing that shows how the parts of a circuit are connected.
 Electrical symbols are used to represent each part of the circuit.
Wire
Battery
+
_
Bulb
Resistor
Switch
SERIES AND PARALLEL CIRCUITS
SERIES CIRCUIT
One path to follow
(See board drawing)
Same throughout the circuit
Different in different parts of
the circuit
Add together
Criteria
Circuit Diagram
PARALLEL CIRCUIT
More than one path to follow
(see board drawing)
Current
Different in different parts of
the circuit
Voltage
Same throughout the circuit
Resistance