Describe under what biasing voltage current can flow through

Describe under what biasing voltage, current can flow through a diode. Also describe under what biasing voltage, no current flows through a diode. Draw the circuit schematics with the labeled current direction (use conventional current direction) and voltage polarity over a diode when A diode is under a forward-biasing voltage. A diode is under a reverse-biasing voltage. Explain under what biasing voltage a diode can be modeled as an open switch or a closed switch. Explain how a rectifier circuit uses diode(s) to convert an AC voltage to DC voltage. Explain the function of the following special diodes: Light produced by an LED (light-emitting diode). Constant breakdown voltage of a Zener diode.

Solution

(6) Under the breakdown voltage of diode it will not conduct that menas there is no current flowing through diode

whenever we apply the breakdown voltage it enters into conduction when it is connected in forward bias mode

If it is made with silicon material Breakdwon Voltage is 0.7 V

If it is made with Germanium material Breakdwon Voltage is 0.3 V

(7)

Attached diagram will represent the circuit schematic of diode in forward and reverse bias mode of operations

(8)

Under forward bias mode Diode will acts as a closed switch

Under Reverse bias mode Diode will acts as a Open switch

(9)

Rectifier is a circuit which converts applied ac signals into dc signals

they can be two types

1) Half Wave Rectifier-Controls only One half cycle in one complete cycle

2) Full wave Rectifier-Controls both half cycles in one complete cycle

10)

a) LED is a light emitting Diode which develops light based on the absored energy

b) Zener diode is special PN diode which can be designed to control or regulate the voltages in reverse bias conditions its acts as a Voltage regulator. Circuit representation of Zener is as follows drawn in below figure