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Current. Current. There are two kinds of current:. Current. There are two kinds of current: Direct current. Current. There are two kinds of current: Direct current Alternating current. Direct current. Direct current. DC flows in one direction
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Current • There are two kinds of current:
Current • There are two kinds of current: • Direct current
Current • There are two kinds of current: • Direct current • Alternating current
Direct current • DC flows in one direction • DC is the kind of current that comes from batteries.
Alternating current • AC flows back and forth rapidly. • In North America it flow back and forth 60 times a second. This is called 60 Hertz
Why we use AC instead of DC • AC can be more easily transmitted over long distances than DC.
Why we use AC instead of DC • AC can be more easily transmitted over long distances than DC. • Why?
Why we use AC instead of DC • AC can be more easily transmitted over long distances than DC. • Why? • Because of transformers
Step-up transformers • Turns lower voltages into higher ones • Fewer turns on the primary side than the secondary one.
Step-down transformers • Turns higher voltages into lower ones. • More turns on the primary side than the secondary one.
Electromagnetic Induction • E.i. describes the production of electricity by using a magnetic field. • This is how generators “make” electricity. • Generators convert mechanical energy into electrical energy.
POWER • Power is the rate at which devices use energy.
POWER • Power is the rate at which devices use energy. • The unit of power measurement is the watt (W). It measures how many units of energy are used per second.
POWER • Power is the rate at which devices use energy. • The unit of power measurement is the watt (W). It measures how many units of energy are used per second. • Energy is measured in joules (J)
POWER • The power rating of a device is directly proportional to the current flowing through the device and the voltage in the circuit.
POWER • The power rating of a device is directly proportional to the current flowing through the device and the voltage in the circuit. • In other words...
POWER • The power rating of a device is directly proportional to the current flowing through the device and the voltage in the circuit. • In other words... The Power Formula Power = current x voltage P = I x V
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