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

Current

  • 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

Resistance

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

Impedance

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

Inductance

  • 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

Capacitance

  • The ability to store charge
  • SI = Farad

Frequency

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

Amplitude

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