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Electricity. Static, Currents, Circuits. Electrical Fields. Is a force field that surrounds an electric charge or group of charges Similar to force field that surrounds a mass – gravitational field. Electrical Fields. Electric field has magnitude and direction
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Electricity Static, Currents, Circuits
Electrical Fields • Is a force field that surrounds an electric charge or group of charges • Similar to force field that surrounds a mass – gravitational field
Electrical Fields • Electric field has magnitude and direction • Vector quantity represented with electric field lines (out from positive, in to negative)
Electricity that moves… • Current: The flow of electrons from one place to another. • Measured in amperes (amps) • Kinetic energy
There are 2 types of currents: • Direct Current (DC) – Where electrons flow in the same direction in a wire.
There are 2 types of currents: • Alternating Current (AC) – electrons flow in different directions in a wire
AC vs. DC • AC/DC: What's the Difference?
What is Resistance? • The opposition to the flow of an electric current, producing heat. • The greater the resistance, the less current gets through. • Good conductors have low resistance. • Measured in ohms.
What Influences Resistance? • Material of wire – aluminum and copper have low resistance • Thickness – the thicker the wire the lower the resistance • Length – shorter wire has lower resistance • Temperature – lower temperature has lower resistance
Electrical Potential Energy • Energy a charge has due to its location in an electric field • Just as GPE is the work required to lift object, EPE is work done to push charge against the electric field of something else that is charged.
What is Voltage? • The measure of energy given to the charge flowing in a circuit. • The greater the voltage, the greater the force or “pressure” that drives the charge through the circuit.
Difference b/t Volts and Amps • Example – you could say that… • Amps measure how much water comes out of a hose. • Volts measure how hard the water comes out of a hose.
Ohm’s Law • Resistance = Voltage / Current • Ohms = Volts / Amps
Circuits • Complete path for electrons to flow (circuit) Battery and Light bulb • Electrons flow from negative terminal to positive terminal
How can we control currents? • With circuits. • Circuit: is a path for the flow of electrons. We use wires.
Circuits: • For electricity to flow a circuit must be closed:
There are 2 types of circuits: • Series Circuit: the components are lined up along one path. If the circuit is broken, all components turn off.
There are 2 types of circuits: • Parallel Circuit – there are several branching paths to the components. If the circuit is broken at any one branch, only the components on that branch will turn off.
Parallel Circuit Series Circuit
Conductors vs. Insulators • Conductors – material through which electric current flows easily. • Insulators – materials through which electric current cannot move.
Conductors: Metal Water Insulators: Styrofoam Rubber Plastic Paper Examples