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DAILY QUESTION March 30, 2009. What is a schematic diagram?. Agenda 3/30/09. Daily Question Check in: 16-2 Worksheet 5 min Preview Time Sect 3 Vocab Pretest 16-3 Notes Assignments: 1. No assignment. Electric Circuit. Is a path through which charges can be conducted
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DAILY QUESTION March 30, 2009 • What is a schematic diagram?
Agenda 3/30/09 • Daily Question • Check in: 16-2 Worksheet • 5 min Preview Time • Sect 3 Vocab Pretest • 16-3 Notes • Assignments: 1. No assignment
Electric Circuit • Is a path through which charges can be conducted • A closed circuit is when there is a complete path for electrons to follow • An open circuit is when there is an incomplete path, there is no charge flow, and therefore no current
Switches • Interrupt the flow of charges in a circuit • Used to open or close a circuit • Knife switch • Uses a metal bar to close the circuit so the electrons can flow
Schematic Diagrams • Used to represent circuits • Dipicts the construction of an electrical circuit • Use standard symbols • Table 2 on page 548
Series Circuits • Have a single pathway for charges to flow • The amount of charge that enters equals the amount of charge that exits • In the devices on the circuit, • Current is the same • Resistance may be different • Voltage may be different • If 1 device is removed, the circuit will not work
Parallel Circuits • Have multiple paths for current • In the devices on the circuit, • The voltage is the same • The current may be different • The sum of the currents in all of the devices equals the total current • If 1 device is removed, the charges would still move through the other loop
Electric Power • Electric power is the rate at which electrical energy is used in a circuit • Electric power is the product of total current (I) in and voltage (V) across a circuit Power (P) = current (I) x voltage (V) • SI unit for power is: watt (W)
The unit of energy that electric companies use to track consumption of energy is the kilowatt-hour. • Electric meters are used to determine how much electrical energy is consumed over a certain time interval
Overloaded Circuits • When electrical wires carry more than a safe level of current • May cause fires • Short circuits occur when two wires accidentally touch, creating an alternative pathway for current
Fuses • Prevent overloading of circuits • A fuse is a ribbon of wire with a low melting point • A “blown out” fuse is a sign that a short circuit or a circuit overload may exist
Circuit Breakers • Uses a magnet or bimetallic strip that responds to current overload by opening the circuit • Acts as a switch • Can be reset