Chapter 6 / Section 2 Electric 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? Copyright © McGraw-Hill Education Electric Current

Electric Current

Electric Current The flow of electric charge.

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

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

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

Voltage Difference Relates to the force that causes electric charges to flow. Electric Current moves from higher voltage to lower voltage.

Electric Circuits

Electric Circuits A closed path that electric current follows. If the circuit is broken, there is no current.

Batteries Supply voltage difference to keep current flowing in a circuit.

Batteries Supply 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. Copyright © McGraw-Hill Education Electric Current

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. Copyright © McGraw-Hill Education Electric Current

Outlets There are 120 V of difference between the two slots in an outlet. The voltage difference that runs or charges your devices.

Resistance

Resistance A resistor resists energy flow and converts it into other forms of energy, such as thermal. Resistance is measured in ohms (Ω).

Resistance A resistor resists energy flow and converts it into other forms of energy, such as thermal. Resistance is measured in ohms (Ω).

Ohm’s Law Ohm'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: Copyright © McGraw-Hill Education Electric Current

AC/DC AC= Alternating Current. Used in US Households DC = Direct Current. Battery-powered devices, such as flashlights, use direct current.

Review Electric Current Voltage Difference Batteries Resistance / Resistors Ohm’s Law AC/DC What current runs American Households?