Electric Current 

Key Terms and Concepts

Electric Circuit -a complete pathway that allows electrons to flow

• simple circuit includes: battery, conducting wires, and a buzzer
• chemical energy in the battery gives the electrons on the negative terminal electric potential energy
• these electrons area attracted to the positive terminal of the battery
• electrons are pushed from the negative terminal of the battery along the conducting wires through a load and end up on the positive terminal
• voltage is what pushes electrons around a circuit, without it electrons will move in different directions
• when  battery is connected to complete circuit, charge will flow continuously through the circuit

Why it doesn’t take time for something with electric energy to turn on even though potential energy exists

• As soon as the battery is connected to the circuit, and the circuit is closed, electrons in every part of the circuit are pushing
• e.g. water in a hose connected to the tap, if the hose is already filled with water, as soon as it is turned on water will come out of the house
• the electrons leaving the negative terminal push the electrons ahead of them, just like the water coming from the tap will push the water ahead of it.
• electrons apply an action-at-a-distance force, meaning that they do not need to touch in order to move other electrons

Electric Load -any device that transforms electrical energy into other forms of energy

• e.g. a buzzer, heater, and motor

Circuit Diagrams -diagrams that use symbols to represent the different components of a circuit

• gives an organized representation of an actual circuit
• even the most complex circuits are only composed of the four basic components

Source -source of electrical energy (e.g. light bulb)

Conductor -the wire through which electric current flows

Load -device that transforms electrical energy into other forms of energy

Switch -device that can turn the circuit on or off by closing or opening the circuit

Circuit Symbols -symbols that help simplify complex circuits in a diagram 

Current -steady and continuous flowing movement of something

Current Electricity -the continuous flow of charge in a complete circuit

Electric Current -amount of charge passing a point in a conductor every second

Amperes -unit for measuring electric current (A)

• in honour of French physicist André-Marie Ampère
• small currents are measured in milliamperes (mA)
• 1.0 A= 1000mA

Conventional Current                                                                                                                                                                                                              Benjamin Franklin classified objects with a build-up or excess of electrical build-up to be positive and objects with the shortage of electrical fluid to be negative. His idea suggests that whenever electricity flows, it moves from positive to negative. However, this idea is the opposite idea to the one we use today. Purely, for historical reasons Franklin’s idea is now named the conventional current.  

Short Circuit -happens when the current going through wires does not travel the correct path of the electrical current

• the current takes a 'short cut' and bypasses part of the circuit
• can result in the electricity not reaching its intended location, such as an electrical outlet

Ammeter -device used to measure the current in a circuit