CircuitS

• Circuit symbols?

  .

  A)

  
• Voltmeter placed parallel to the component ammeter placed in series with the circuit 


  .

  
• GOING TO LOOK AT THE CHARACTERISTICS OF A

  LAMP

  DIODE

  VARIABLE RESISTOR
• A variable resistor graph will be a straight line that goes through the origin meaning as the potential difference you have a greater current that flows as resistance is constant. Example of an ohmic conductor
• A filament lamp will however will have an s shape as when it gets hotter it gives out more and more light and the resistance increases

  
• A diode graph however will not pass through the origin as it only allows current to flow in one direction so it will be a steep curve up from the origin

  .

  
• Thermistor and LDR will both have a curved line downwards. Why?

  -It showcases that if light or heat increases the resistance goes down. Therefore at high light or heat the circuit has low resistance and vise versa

  
• Two types of circuits:

  Series and parallel

  Parallel circuits have more than one branches meaning there are more pathways for the current to flow
• This means parallel circuits have different current throughout as it is split

  However the potential difference of each loop in a parallel circuit is the same

  I represents the current in both circuits and V represents PD

  Series

  i1=i2=13 V1=V2+V3

  Parallel

  i1=i2+i3 V1=V2=V3

  
• When looking at resistance in a Series Circuit Total resistance = R1+R2 (add R3 and R4 for example if there are more than 2 components)

  Parallel circuit its important to note that Total resistance would be lower than R1 and Lower than R2 (Not combined. Generally lower)
• To find the resistance in a parallel circuit you make the Resistance its reciprocal and add them

  An example of this is

  R1=5 R2=2

  1 1

  --- + -- = 0.7 Ohms

  5 2