Semiconductor Fundamentals Unit 2 – Diodes and Half-Wave Rectification
UNIT 2 – DIODES AND HALF-WAVE RECTIFICATION
UNIT OBJECTIVE
At the completion of this unit, you will be able to demonstrate the principles of semiconductor
diode operation and diode half-wave rectification by using diode test circuits.
UNIT FUNDAMENTALS
Diodes normally permit electron current flow in only one direction, as illustrated. When N type
semiconductor material is joined to P type material, a depletion region is formed near the
junction. An additional voltage potential is required to pass current through the depletion region
of the diode junction.
The extra voltage potential required at the depletion region of a diode semiconductor junction is
the barrier voltage. The barrier voltage for germanium diodes is about 0.3V and for silicon
diodes is about 0.6V (0.5V to 0.7V).The barrier voltage is also called the diode forward voltage
drop (VF).
When a negative voltage is applied to the cathode of the diode, electrons in the N type material
are forced closer to the junction.