Current and Potential difference

• The higher the potential difference, the higher the current will be
• The potential difference is that pushing the current around the circuit, measured in volts
• Resistance is a measure of how easily charge can flow, measuring in ohms
• Equation for current

  Current = charge / time

  Symbols: I = Q / T

  Units: A = C / S
• Potential difference is the energy transferred per unit of charge
• Equation for potential difference

  Potential difference = energy transferred / charge

  Symbols: V = E / Q

  Units: V = J / C
• I-V Graphs are linear, as the current and potential difference are proportional. The gradient of the line depends on the resistance
• The I-V graph with a filament lamp is curved, as the increased temperature of the lamp makes the resistance increase, curving the gradient
• The higher the temperature, the higher the resistance
• In diodes, current only flows in one direction, so the gradient (resistance) in an I-V graph will continue to increase in one direction

  
• When particles have more energy they vibrate more. The more vibrations make it more difficult for them to pass through the resistor