Chapter 6 / Section 2ELECTRIC CURRENT

Section 2: Electric Current

An electric current is a flow of electric charge.

Essential Questions When and how does a voltage difference produce an electric current?

How do batteries produce a voltage difference in a circuit? How does Ohm’s law relate current, voltage difference, and resistance?

Electric CurrentCopyright © McGraw-Hill Education

Electric Current

Electric Current The flow of electric charge.

Electric CurrentThe flow of electric charge.Net movement of electric charges in a SINGLE DIRECTION.

Electric CurrentThe flow of electric charge.Net movement of electric charges in a SINGLE DIRECTION.Measured in Amperes (A)

Electric CurrentThe flow of electric charge.Net movement of electric charges in a SINGLE DIRECTION.Measured in Amperes (A)

Voltage DifferenceRelates to the force that causes electric charges to flow.

Electric Current moves from higher voltage to lower voltage.

Electric Circuits

Electric CircuitsA closed path that electric current follows.

If the circuit is broken, there is no current.

BatteriesSupply voltage difference to keep current flowing in a circuit.

BatteriesSupply voltage difference to keep current flowing in a circuit.Dry Cell: (paste)chemical reaction occurs to cause voltage difference (common battery)Wet Cell: (liquid) Car Battery

Dry-Cell Batteries

A cell consists of two electrodes surrounded by a material called an electrolyte. The electrolyte enables charges to move from one electrode to the other.

One electrode is the carbon rod, and the other is the zinc container.

The electrolyte is a moist paste containing several chemicals.

The cell is called a dry cell because the electrolyte is a moist paste, and not a liquid solution.

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Wet-Cell Batteries

A wet cell contains two connected plates made of different metals or metallic compounds in a conducting solution. A wet-cell battery contains several wet cells connected together.

Electric CurrentCopyright © McGraw-Hill Education

OutletsThere are 120 V of difference between the two slots in an outlet.

The voltage difference that runs or charges your devices.

Resistance

ResistanceA resistor resists energy flow and converts it into other forms of energy, such as thermal.

Resistance is measured in ohms (Ω).

ResistanceA resistor resists energy flow and converts it into other forms of energy, such as thermal.

Resistance is measured in ohms (Ω).

Ohm’s LawOhm's law measures the resistance of objects and materials. If I stands for the electric current, Ohm's law can be written as the following equation:

Electric CurrentCopyright © McGraw-Hill Education

AC/DCAC= Alternating Current.

Used in US Households

DC = Direct Current. Battery-powered devices, such as flashlights, use direct current.

ReviewElectric CurrentVoltage DifferenceBatteriesResistance / ResistorsOhm’s LawAC/DCWhat current runs American Households?