This document provides an overview of current electricity, including: - Current electricity involves a continuous flow of charged particles through a conductor, measured in amperes. - Electric circuits form a closed loop through which current can flow. A difference in electric potential provides the incentive for current to flow. - Voltage is a measure of the difference in electric potential and provides the force for current to flow. Batteries use chemical reactions to produce electricity between two electrodes. - Resistance opposes the flow of current and is affected by the material, length, and diameter of a conductor. Ohm's law describes the relationship between voltage, current, and resistance in a circuit.

1. Current Electricity

2. Electricity Electricity is: the movement of charged particles from one place to another.

3. Static vs. Current How is static electricity different than current electricity? Static electricity involves a build-up of electric charge with a singular, momentary discharge. Current electricity pertains to a continuous flow of electricity through a conductor. Name two examples of each. Static : lightning, static shock Current : wall outlet, battery

4. Current Electricity A constant flow of charged particles through a conductive medium Measured in Amperes (A) 1 Amp = 6 billion billion electrons per second moving past a point

5. Circuits An electric circuit is a closed path of conductors through which current can flow similar to water flowing through a pipe

6. Current Flow Electrons need some incentive to get started in order for electricity to flow. A difference in electrical potential (build-up of charges) provides the force required for current to flow Potential Difference: a measure of the difference in charges (electric PE) between two points also called Electro-Motive Force (EMF) or Voltage this force causes work to be done (current to flow) measured in Volts

7. Voltage Voltage is the force created by a difference in electrical potential similar to water pressure Voltage examples: AA battery: 1.5 V 9 Volt battery: 9 V Car battery: 12 V Household outlet: 120 V Electric chair: 1000 - 2450 V

8. Batteries Cells are individual compartments in a battery that produce energy Chemical reactions take place which produce electricity two electrodes (electron conductors) each electrode is made of a different material electrolyte liquid or paste allows ions to flow between

9. Inside Batteries Electrodes: one material donates electrons negative electrode (anode) connects to - terminal (outside) other material accepts electrons positive electrode (cathode) connects to + terminal Electrolyte: paste in dry cell i.e. alkaline (basic pH) liquid in wet cell i.e. sulfuric acid Dry Cell Wet Cell

10. Resistance Resistance is the tendency of a material to oppose current measured in Ohms ( Ω ) conductive materials have lower resistance increased resistance can produce heat & light i.e. tungsten filaments in light bulbs Resistors in electronics control the flow of electricity

11. Resistance Resistance affects voltage (force) and current (amount) of electricity flow Resistance is affected by: conductivity of the material length of wire (longer wire = more resistance) diameter of wire (wider wire = less resistance) temperature in metals higher temps = more resistance in carbon/silicon higher temps = less resistance

12. Ohm's Law Voltage = Current x Resistance (V) volts (I) amps (R) ohms V = I • R Current = Voltage  Resistance I = V/R Resistance = Voltage  Current R = V/I Georg Simon Ohm (1787 - 1854)

13. Ohm's Law if I (current) = .005 amps and V (voltage) = 10 volts what is the resistance ( R )? What formula should we use? R = 10V/.005A Resistance = 2,000 Ω R = V/I

14. DC & AC Direct Current (DC): electrons flow in one direction only current flows from negative to positive example: batteries Alternating Current (AC): the direction of current changes rapidly over time electrons change direction (move back and forth along a conductor) 60 times every second positive & negative terminals constantly change example: household wiring