Transistors & Capacitors


Semi Conductors:

  • A semi conductor is an element which has 4 electrons in its valence orbit ex carbon
  • If a small amount of another element (phosphorus, Aluminium) is added to the semi conductor material, the new crystal will have either extra electrons ( N-TYPE) of too few electrons ( P-TYPE)
Image result for semiconductor


  • Term Diode means ” two Element”
  • A small voltage develops where the crystals join called the barrier voltage
  • Diodes have polarity , Neg lead is short, Pos is long lead (backward does not work)


  • capacitor is a device that stores electrical energy in an electric field. It is a passive electronic component with two terminals. The effect of a capacitor is known as capacitance.
  • Basic function of a capacitor is to store electrical energy by building up a voltage between the metal plates.
  • Capacitance is measured in Micro Farads (MF)
  • Capacitors also have a voltage rating which is the maximum voltage that is normally safe to apply across the leads
  • Electrolytic Capacitors are polarized( pos and Neg leads) and care must be taken when installing them.