This document discusses different types of diodes: - Light-emitting diodes (LEDs) emit light when current flows through them as electrons recombine with electron holes. - Zener diodes allow current to flow in the forward bias direction but conduct in the reverse bias direction once the breakdown voltage is reached, acting as a voltage regulator. - Shockley diodes have four layers and stay on once turned on or off once turned off, like a thyristor without a gate terminal. - Varactor diodes act like variable capacitors, changing capacitance in a circuit when a constant voltage is present.

1. DIFFERENT TYPES OF DIODES
Mehedi Hasan Masud
Lecturer, Dept. of EEE
DIU

2. A light-emitting diode (LED) is a semiconductor light
source that emits light when current flows through it.
Electrons in the semiconductor recombine with electron
holes, releasing energy in the form of photons.
Light Emitting Diode(LED)

3. It is a passive element which works under the principle of
‘Zener Breakdown’. it is similar to normal diode in
forward bias condition i.e., it allows current to flow.
But in reverse bias condition, the diode conducts only
when the applied voltage reaches the breakdown voltage,
known as Zener Breakdown. It acts as voltage regulator
Zener Diode

4. Shockley Diode has four layers. It is also
called as PNPN diode. It is equal to a thyristor
without a gate terminal, which means the gate
terminal is disconnected. As there is no trigger
input, the only way the diode can conduct is
by providing forward voltage.
It stays ON once it turned “ON” and stays
OFF once it turned “OFF”.
Shockley Diode

5. Also known as Varicap diodes. It acts like the
variable capacitor. Operations are performed mainly
at reverse bias state only. These diodes are very
famous due to its capability of changing the
capacitance ranges within the circuit in the presence
of constant voltage flow.
Varactor Diode