Electricity

• There are 2 types of current flow, which are:

  • Conventional Current Flow (CCF): When the electrons come out from the (+) terminal and go back in through the (-) terminal (This type is mostly used for counting).
  • Electron Current Flow (ECF): When the electrons come out from the (-) terminal and go back in through the (+) terminal (This type is the one that actually happens in real life).
• There are 2 types of circuit arrangement, which are none other than: 

  • Series Circuit:
  • Only have 1 way for electrons to flow
  • No branches
  • Parallel Circuit:
  • Has more than 1 way for electrons to flow
  • Has branches
• Electron: Has a negative charge, some electrons in a metal are free to move. Electrons move randomly in a metal, but when put in a circuit, all electrons move in the same direction (can only flow in a completed circuit). Since it has a negative charge, electrons are attracted to the positive terminal and repelled from the negative terminal. 
• Circuit Component: 

  • Cell (Battery if containing 2 or more cells): Provides energy to make current flow, and two connections (terminal), a positive terminal and a negative terminal. They are labeled with positive (+) and negative (-). A cell stores chemical energy that can be changed to electrical energy in a circuit. 
  • Resistor: Limits the flow of electrons/ current. The symbol is ( R ). 
  • Lamp/ bulb: Gives out light (Even though they are different types of lamp, we still use the same bulb symbol)
  • Buzzer: Makes a buzzing sound
• Circuit Component:

  • Voltmeter: To measure the potential difference of the current. It’s symbol is ‘V’ (Call it volt for short), and it must be placed before and after the lamps (Only in placed in parallels)
  • Omega: Its symbol is ‘Ohm’
  • Alpha
• Circuit Diagram: Circuits can also be represented in drawings. Circuit diagrams has lots of advantages, for example: 

  • Easier to draw
  • Have standard symbols
  • Wires are drawn with straight lines which makes it easier to interpret
• When drawing a circuit, make sure: 

  • There are no gaps in the line (Especially at the corners and where wires meet components)
  • Wires are not drawn through components
• Measuring Currents: We measure the currents in a circuit with the help of an ammeter. Currents are measured in units called amps, and the symbol of this measurement is ‘A’.
• • Conductors: Materials that conduct electricity, meaning they allow the electron current to flow/ freely move past them. Examples of conductors are all the metal and some alloy metal ( If the test has a metal that won’t allow electrons through, most likely there are covered with an insulator [most likely paint] )
• • Insulators: Materials that do not conduct electricity, meaning they don’t allow the electron current to flow/ freely move past them. Insulators keep us safe from electricity. Examples of insulators are plastic, wood, air, glass, and cotton. 
• Current In Series Circuit: Adding and removing components can affect the current and the ammeter’s reading. The effects depend on what components are changed
• Current: The moving electrons in a circuit. The current symbol is ‘I’.
• Circuit Component:

  • Wire: Where the electrons/ current moves/ are transport
  • Open Switch: Stops the flow of electrons/ current
  • Closed switch: Starts the flow of electrons/ current
  • Ammeter: Measures current in a circuit. An ammeter has 2 terminals to attach the wires, the red terminal of the ammeter must be connected to the positive wire in the circuit, while the black terminal of the ammeter must be connected to the negative wire in the circuit (Only placed in series)
• Adding/ removing cells: When we have more cells in a circuit, we have more chemical energy to change into electrical energy. So if we add more cells into the series circuit, the ammeter reading will be doubled, the current will flow faster, and the lamp will be brighter. Therefore, removing more cells makes the current slower, the ammeter reading will decrease, and the lamp will be dimmer.
• • We must be careful when adding cells though, the energy might be too much that it could cause the lamps to be damaged or the wires to get hotter and hotter. 
• Adding/ removing lamps: When the electrons pass through a lamp, it will transfer some of its electrical energy to it, thus making the current slower. So if we decrease the amount of lamps in the circuit, the ammeter reading will increase, the other lamps will be brighter, and the current will flow faster. Therefore, if we increase the amount of lamps, the ammeter reading will decrease, the current will move even more slower, and the lamps will be even more dimmer.