Electricity Facts

Electricity Facts


  • A coulomb is charge, an amp is current [coulomb/sec] and a volt is potential difference [joule/coulomb].
  • Short fat cold wires make the best conductors.
  • Electrons and protons have equal amounts of charge (1.6 x 10-19 coulombs each).
  • Adding a resistor in parallel decreases the total resistance of a circuit.
  • Adding a resistor in series increases the total resistance of a circuit.
  • All resistors in series have equal current (I).
  • All resistors in parallel have equal voltage (V).
  • If two charged spheres touch each other add the charges and divide by two to find the final charge on each sphere.
  • Insulators contain no free electrons.
  • Ionized gases conduct electric current using positive ions, negative ions and electrons.
  • Electric fields all point in the direction of the force on a positive test charge.
  • Electric fields between two parallel plates are uniform in strength except at the edges.
  • Millikan determined the charge on a single electron using his famous oil-drop experiment.
  • All charge changes result from the movement of electrons not protons (an object becomes positive by losing electrons)