Application of Diode

Application of Diode

1. Rectifier diodes or rectifier is an electrical device which converts an alternating current (ac) into a direct current (dc) by passing a current to flow through it in one direction only

 Half-wave rectifier: a half-wave rectifier is comprised of a single diode that connects an AC source to a load. As shown in the figure the load is represented by a simple resistance. The diode conducts on AC voltage only when it is forward biased that is an anode is positive with respect to the cathode (and voltage greater than 0.7 V for a silicon diode i.e. cut in voltage). The output has therefore only a positive component with an average value given in formulae:

Circuit and output graph is shown in below figure

Half wave rectifier

The AC current, according to its direction and position of a diode, flows either in the top or in the bottom part of the bridge in each half-cycle.

Full-wave rectifier

In half-wave rectifiers, only half of the power has generated an average and RMS no-load output voltages of an ideal single-phase full-wave rectifier are half of the power provided by the source is not used. To increase power and solve this problem, full-wave rectifiers are used. The full-wave rectifier is composed of two diodes (but it requires a center tapped transformer), maybe four diodes in case of a bridge rectifier. The figure shown below is a bridge rectifier, composed of four diodes that can use a “normal” transformer

The value of average and voltages of an ideal single-phase full-wave rectifier are given by the following equation

Other application areas of Diode are:

1. Isolating signals from a supply
2. Voltage Reference
3. Controlling the size of a signal
4. Mixing signals
5. Detection signals