Current & Voltage

• (I) Current:

  • rate of flow of electrical charge.
  • amount of charge passing through a fixed point per unit of time.
  • measured in amperes/amps (A)
• Measuring current:

  • can be measured with an ammeter.
  • ammeters must be connected in series with the component being measured.
• Calculating current:

  • 1 amp= charge of 1 coulomb (electrical charge) flowing in 1 second.
  • size of an electric current = amount of charge passing through a component each second.
  • $I\ =$$\ \frac{Q}{T}\$(current =$\frac{current}{time}$)
• Q= charge flowing measured in coulombs

  I= current measured in amps

  t= time measured in seconds

  
• (V) Voltage:

  • electrical force done per unit of charge flowing between 2 points.
  • it is the difference in electrical potential energy between 2 points.
  • higher the voltage, the greater the force and more energy each electron carries as it flows.
• Voltage:

  $V=$$\ \frac{W}{Q}$ (voltage = $\frac{work\ \left(J\right)}{ch\arg e\ \left(C\right)}$)

  • V= voltage
  • W= electrical work done by the charge (J)
  • Q= charge flow (C)
  • potential difference/voltage measured using a voltmeter.
  • voltmeters must be set up in parallel with the component measured.