Chapter 19 current electricity

Electric current

movement of charged particles

Current is the rate of…

charge transfer

Current unit and symbol

Ampere, I

Conventional Current

positive charge movement

What is current motion made up of?

Positive, negative, or mixed motion. Positive and negative motion is called charge carriers

Resistance

Impedes/ opposes the motion of charge through a conductior

Resistance symbol and unit

R, ohms

Resistance depends on…

Length, temperature, thickness, and composition of a substance

What makes a strong resistance?

Lower area, longer material, higher temperature

What makes a weak resistance?

Greater area, shorter material, lower temperature

Ohms law only applies to…

Ohmic materials - materials that have a constant resistance

Howe many paths do series circuits have?

1 path

How many amps of current does each device receive in a series circuit

each device receives the same amount

About how many J/C of voltage does each device receive in a series circuit

A little less through each device because each time it passes through a device it will use up some voltage

The sum of potential difference across each device equals…

the total potential delivered to the circuit

Total resistance in a series circuit is equal to…

the sum of each resistor’s resistance

Resistance does not change the…

voltage

Voltage dividers

series circuits that uses up some voltage from a high voltage source when a lower potential difference is required

How many paths are in a parallel circuit

multiple

How much is the current total in a parallel circuit?

It is the sum of the currents on the paths

In a parallel circuit, the branches are…

independent of each other, changing something in one path does not affect the other paths

when do short circuits occur

when resistance is low due to a high current

Direct current

electrons move in one direction, high to low potential

Convential current is flow of..

positive terminal to negative terminal

alternating current

terminals causing potential, difference are constantly changing sign causes charges to vibrate instead of flow

batteries convert chemical energy to electrical energy

electrical energy converts into internal energy

electric power

rate of energy conversion

Power symbol and unit

E, Joule also measured at kwh