electricity

• circuit symbols

  
• Switch on

  
• Cell symbol

  
• Battery symbol

  
• diode

  
• resistor

  
• variable resistor

  
• LED

  
• Lamp symbol

  
• fuse

  
• voltmeter

  
• ammeter

  
• thermistor

  
• LDR- light dependent resistor

  
• V=Voltage in Volts which measures electric pressure, electric tension, or potential difference
• I= Current in Amps which measures the rate of flow of electric charge through a surface.
• R=Resistance in Ohms (Ω) - The measure of how difficult it is for the current to flow through a component
• Q= electric charge in coulombs
• Ohms law triangle=

  Voltage

  ----------------------

  Current x Resistance
• V (voltage)

  ------------------------

  I(current) x R(resistance)
• Series circuits

  
• Parallel circuit

  
• Series circuit- a circuit that has no branches and the electricity travels through it in a loop.
• Parallel circuit- circuits where there are different components connected by branches on the wire, you can only pass through the components if you follow all of the branches
• Parallel circuits are useful if you want components to continue to work, even if one component has failed. This is why our homes are wired up with parallel circuits.
• Series circuits are useful if you want a warning that one of the components in the circuit has failed. They also use less wiring than parallel circuits.
• The current in a series circuit is the same at all places in the circuit.
• • The supply voltage is shared between components in a series circuit.
  • The sum of the voltages across components in series is equal to the voltage of the supply.
• The current in a parallel circuit splits into different branches then combines again before it goes back into the supply. When the current splits, the current in each branch after the split adds up to the same as the current just before the split.
• The voltage across components in parallel is the same for each component.
• • The flow of charge (C) = current (A) x time (s).
• energy transferred= voltage x charge
• Rectifier

  
• A thermistor is a component where resistance changes with its temperature.
• A diode is a component where current travels in one direction, making them rectifiers as the diode blocks the alternating current when it changes direction
• a rectifier is a component that changes an alternating current into a direct current,
• resistance= potential difference/ current
• electrical work done= current"2 x resistance
• electrical work done= current x voltage