Chapters 20-21: Electricity and Circuits

Types of electric charge

+ and -

Coulomb C

unit for electric charge

Electrically neutral

when protons (positive) and electrons (negative) are equal

Protons

positive electric charge

Electrons

negative electric charge

Neutrons

neutral electric charge

A charged object

when the net change of an object is NOT zero (it’s unbalanced)

Static electricity

SMALL temporary inbalance of protons and electrons

Electricity

charge and current; caused by CHARGES!

Current

flow of electricity

Circuit

path of current

Resistor

control current level (like a remote)

Switch

stopping or allowing the flow of current

Closed circuit

completes the current

Open circuit

current interrupted (thus open)

Ampere A

unit for current

Voltage

measure of electrical potential energy

Volt

unit for VOLTage

Multimeter

Measures current, voltage, and resistance

Battery

transform chemical to electrical (it’s the power of a circuit)

Flow of electricity

+ to - (high Potential Energy to low Potential Energy)

Conservation of Energy

all inputted electricity equals the outputted energy (all energy remains in the circuit)

Energy

difference in voltage

1 amp

difference in 1 volt

1 volt

does 1 watt (1J/1S) in a second

Resistance

the amount an object resists current flow

Ohm

unit for resistance

Ohm’s Law

current is DIRECTLY related to voltage and INVERSELY to resistance

V=IR

Conductor

low resistance (like metal)

Insulator

high resistance (plastic, current doesn’t flow thru)

Semiconductor

has some qualities of conductors and insulators (like silicon)

Potentiometer (Pot)

resists current based on strength applies (on a dial)

Low resistance

high current

Electrical devices

resistors

Stable current

Ohm’s Law is ONLY applicable when there’s…

Series circuit

only 1 path of current (equal current at all parts of it)

Voltage Drop

difference of voltage in a device with current flow

Kirchoff’s Voltage Law

total voltage drop in a series circuit MUST EQUAL voltage from battery

Total resistance

resistance added together

Parallel circuit

has more than 1 path of current (branches)

Kirchoff’s Current Law

all entered current must exit again

Short circuit

branch in a circuit with little to no resistance (or a “shortcut” that reduces the amount of current)

Circuit breaker

switch; turn off when curcuit overloads

Fuse

when a wire burns or melts due to an overloaded curcuit

Voltage in parallel circuit

is constant along the same wire

Devices in a parallel circuit

all devices don’t need to be on; it can vary

Electrical power

rate that electrical energy is changed into other forms of energy

kilowatt

kW

kilowatt-hours

kWh

DC

direct current in 1 DIRECTION

AC

alternating current that reverses direction

Ground Fault Interrupt (GFI) outlet

outlet with auto device which protects from electric shock

Transformer

converts high-voltage to lower voltage

Current of a parallel circuit

more current at the same voltage