Wiii: Explain the electrical concepts of current, potential difference, resistance, impedance, inductance, capacitance, frequency and amplitude as they relate to biological signals and biomedical apparatus


  • The flow of electrical charge (SI = Ampere, which is 1 coulomb/sec)
  • Coulomb is the the SI of electrical charge

Potential Difference

  • The work done per unit charge
  • Measured in Volts (V)
  • PD of 1V means 1 joule of work is done per coulomb of charge


  • The difficulty a charge has flowing across a potential difference
  • SI unit = Ohms
  • Ohm’s Law: V = IR


  • The opposition that a circuit presents to an electrical current when a voltage is applied


  • A property of an electric circuit by which an electromotive force is induced in it by a variation of current either in the circuit itself or in a neighbouring circuit


  • The ability to store charge
  • SI = Farad


  • The number of cycles that occur per second measured in Hz


  • The maximum displacement (↑ or ↓) by a point on a wave