Static, Currents, Circuits 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.

Resistance = Voltage / Current Ohm’s Law Resistance = Voltage / Current Ohms = Volts / Amps

Practice with Ohm’s Law Volts Amps 4 100 25 15 150 10 2 30 9 45 5 6 48 8

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.

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.

Series Circuit

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 Parallel Circuit

Schematics of Circuits

Equivalent Resistance

Equivalent Resistance

Conductors vs. Insulators Conductors – material through which electric current flows easily. Insulators – materials through which electric current cannot move.

Examples Conductors: Insulators: Metal Water Styrofoam Rubber Plastic Paper