Download 16.2 Current/16.3 CIrcuits

16.2 Current
I CA N:
- R E CA LL T HAT CU R R E NT I S ME A S U R ED I N A MP E R E S ( A ) ,
WHICH IS E QUA L TO O NE CO U LOMB O F CHA R G E P E R
S E CO ND (C/ S ) .
- R E CA LL T HAT P OT E NTI A L D I F F E R ENCE ( VO LTAG E) ACR O S S
A N E NE R G Y SO U R CE I S ME A S UR ED I N P OT E NTI A L
ENE R G Y I N J O ULES AND IS EQUAL TO ONE J OULE (J ) OF
E NE R G Y PE R CO U LO MB O F CHA R G E ( J / C ) .
Voltage and Current
• Electrical potential energy: the ability to move an electric charge
from one point to another.
Electrical Potential Energy and Relative
Postion
• Force can push a charge in the opposite direction.
Potential difference is measured in volts,
creates current
• Potential difference: (between two points) the work that must be
done against electric forces to move a unit charge from one point to
another. (think water pressure)
• Si Unit= volt (V)
• 1 J/C
• Often called VOLTAGE.
• 12 V battery…
• Current: the rate that electric charges move through a conductor.
• SI Unit= ampere
• 1 amp= 1C of charge moving past a point in 1 second.
Electrical Resistance
• The opposition posed by a material or a device to the flow of current.
• More load=more resistance
• Different filaments are put in light bulbs to create more or less
resistance. ie: 40 W v. 100 W light bulbs.
• Resistance= voltage/current
• Conductors have low resistance, while insulators have a high
resistance.
16.3
I CA N:
- E X PLA IN HO W T HE P O WE R S O U R CE S U P P L IE S T HE
E L E CT RO NS A L R E A DY I N A CI R CU I T WI T H E L E CTR IC
P OT E NTIAL E NE R GY B Y D O I NG WO R K TO S E PA R AT E
O P PO SITE CHA R G E S
- R E CO GNIZE T HAT E X P E RI MENT S, I NVE ST IGAT IONS A ND
T EST I NG ( 3 - D O R VIR T UAL) MUST BE USED TO CONST RUCT A
VA R IE T Y O F CIR CU ITS , A ND ME A S U R E A ND CO MPA R E
T HE VO LTAG E A ND CU R R E NT.
- D E SCR IB E HO W E L E CT R ONS T R A NS F ER E NE R G Y TO OT HE R
O B J E CT S A ND T R A NS F O RM E L E CT R ICA L E NE R GY I NTO
OT HE R FO R MS ( E.G ., LIG HT, SOUND, HEAT ) .
- R E CA LL T HAT R E S I S TO RS O P P O S E T HE R AT E O F CHA R G E
F LO W IN A CIR CU I T.
Circuits
• Electric Circuit: set of electrical
components connected such
that they provide one or more
complete paths for the
movement of charges.
• Closed v. open
• Series: the components of a circuit
that form a single path for current
• Parallel: a circuit in which all of the
components are connected to each
side by side.
Electrical Power and Electrical Energy
• Electrical Energy: the energy that is associated with charged particles
because of their positions.
• Power= current (I) x voltage (V)
• SI Unit=Watt (W)
• Fuses: electrical device that contains a metal strip that melts when
current in the circuit becomes too great
• Circuit breaker: switch that opens a circuit automatically when the
current exceeds a certain value.