Voltage, Current and Resistance

Series Circuit
1. Voltage
  1. Shared across all components
  2. V = V1 + V2
  3. Voltage around always adds up to voltage across the battery
    1. Total work done on charge by battery = total work done by charge on components
  4. Adding a cell
    1. Cell voltages add up
      1. C = C1+ C2
2. Current
  1. The same everywhere
    1. All components get the same current
  2. A1 = A2 = A3
  3. Size is determined by total voltage of the cells and resistance of the circuit
  4. Adding cells
    1. Increases voltage but not resistance
      1. Current increases
3. Resistance
  1. Sum of resistances of all components
  2. R = R1 R2
  3. The lager the resistance, the larger the share of voltage the component receives
Parallel Circuit
1. Voltage
  1. P.D is the same across all components
    1. Each component = P.D of battery
  2. V1 = V2 = V3
  3. Identical bulbs in parallel will be same brightness
  4. Adding cells
    1. Total voltage stays the same
      1. Each charge only goes through one cell
      2. C = C1 =C2
2. Current
  1. Adding cells
    1. Increase total current
      1. Current through each cell is less than the rest of the circuit as they join to make the total current
  2. Total current is shared between braches
    1. A = A1 + A2
    2. Current into junction = current leaving
3. Resistance
  1. Always less than that of the branch of the lowest resistance
    1. Charge has more than 1 option, so only some flows across each branch
    2. Circuit with 2 resistors in parallel < resistance than circuit with resistor alone
      1. Parallel has higher current
Types of Current
1. AC
  1. Alternating current
  2. Our mains supply
  3. Allows transformers to work
  4. Easy to generate/ transport
    1. Turn a magnet inside an iron core!
2. DC
  1. Direct current
  2. In batteries
  3. Harder to generate/ transport than AC

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Voltage, Current and Resistance

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	Created by Alice Hathaway about 8 years ago