Electricity, power and electronics, Slides of Family and Consumer Science

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ELECTRICITY, POWER

AND ELECTRONICS

SCIENCE

KEY CONCEPTS:

Electrons Voltage (V) Current (I) Resistance (R) move from negative (–) to positive (+) terminals. pushes electrons (like water pressure in a pipe). is the flow rate of electrons (measured in Amperes, A). opposes electron flow (measured in Ohms, Ω).

INSULATORS

Materials that block the flow of electric current. Examples: Rubber Plastic Glass Ceramic Dry Wood (Used in wire coatings, gloves) (Outlet casings, bottle material) (High-voltage insulators) (Fuse boxes, spark plugs) (Non-conductive when dry)

MEASURING

ELECTRICITY

"Electrical pressure" (measured with a voltmeter). Example: AA battery = 1.5V, Car battery = 12V. Flow rate of electrons (measured with an ammeter). Example: LED uses ~20mA (0.02A). Voltage (V) Current (I) Opposition to electron flow (measured with an ohmmeter). Example: A resistor limits current to protect an LED. Resistance (R)

ELECTRICAL POWER

Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. P = V × I I = Current (amps), V = Voltage (volts), P = Power (Watts)

HOW ELECTRIC CIRCUITS WORK Open Circuit Closed Circuit

SERIES VS. PARALLEL CIRCUITS Series Circuit Parallel Circuit

SERIES VS. PARALLEL CIRCUITS Series Circuit Parallel Circuit Single path for current Multiple paths If one bulb burns out, all stop working Bulbs work independently Used in Christmas lights (old type) Used in home wiring

HOW ELECTRICITY

IS GENERATED

Solar Panels (sunlight → electricity) Wind Turbines (wind → kinetic → electrical energy) Fossil Fuels (coal, gas) Nuclear (uranium fission → heat → steam → electricity) Renewable Sources Non-Renewable Sources

TYPES OF CIRCUITS

When inside a building, circuitry is connected to a switchboard in order to be switched on and off at will Include power circuits, which supply the power sockets or plugs in the building and circuit breakers, which prevent short circuits AC Circuits

ELECTRICAL COMPONENTS

Sensors/detectors: can sense or detect levels of- or changes in - values such as temperature, pressure and light. Control systems: They use feedback from sensors to control devices automatically. Logic gates: They send signals, in the form of low voltages, to other devices. An output signal from the logic gate is switched on or off, depending on the input signals it receives.