p-n Junction Diode as a Rectifier

An AC voltage is bidirectional: its value and its direction of flow both keep changing, retracing the same sinusoidal pattern once every cycle. RECTIFICATION is the process of converting this bidirectional voltage or current into a unidirectional (one-way) voltage or current, and the electronic circuit that performs this conversion is called a RECTIFIER. A p-n junction diode is naturally suited to this job precisely because of its asymmetric conduction: it conducts freely in one bias direction and blocks almost entirely in the other, so connected correctly in an AC circuit it lets current through for only part of each cycle -- exactly the one-way behaviour rectification needs. Rectifier circuits built from p-n junction diodes come in two basic families, distinguished by how much of each AC cycle they manage to make use of: the HALF WAVE rectifier, which uses a single diode and rectifies only one half of each cycle (discarding the other half entirely), and the FULL WAVE rectifier, which uses two diodes arranged so that current flows through t …