What does a Diode do in a Circuit and how it works
If you're studying electronics, or just
tinkering around with circuits, you've probably come across diodes. But what does
a diode do in a circuit? How do they work? In this blog post, we'll take a look
at diodes and their role in electronic circuits. Stay tuned!
My last post was about Relays. If you want to know, what is Relay
and how it works, check out my last post: What does a relay do in a circuit.
What is Diode?
A diode is a two-terminal electronic
component with an asymmetric transfer characteristic, with low resistance to
current flow in one direction, and high resistance in the other.
What does a diode do in a circuit?
Diodes are used to rectify alternating
current (AC) into direct current (DC). They are also used as signal level
clippers, voltage regulators, and in power supplies where they regulate the
output voltage by clipping off the peaks of the AC waveform.
How does a diode work?
The most common type of diode is made
from a semiconductor material like silicon or germanium. When these materials
are doped with impurities, they become conductive and can be used to create
electrical junctions.
When an electrical junction is created,
the impurities on one side of the junction become electrically negative, while
the impurities on the other side become electrically positive. This creates a
polarized region called the depletion layer.
The depletion layer acts like an insulator,
and prevents current from flowing through the diode. However, when a voltage is
applied to the diode in the correct direction, it creates an electric field
that counteracts the depletion layer, and allows current to flow.
Diodes are typically used in circuits
with AC power sources, where they rectify the AC waveform into a DC waveform.
Rectification is the process of converting an alternating current (AC) into a
direct current (DC).
How are diodes used in rectifier circuits?
Rectifier circuits are used to convert AC
power into DC power. The most common type of rectifier circuit is the half-wave
rectifier, which uses a single diode to rectify the AC waveform.
Half-wave rectification can be achieved
by simply connecting the diode in series with the load resistance, as shown in
the diagram below.
As you can see from the diagram, when the
AC voltage is positive, the diode is forward biased and conducts current. This
allows current to flow through the load resistance, and the load voltage rises.
However, when the AC voltage is negative,
the diode is reverse biased and does not conduct. This prevents current from
flowing through the load resistance, and the load voltage falls.
The output of the half-wave rectifier is
a pulsating DC voltage that peaks when the AC input voltage is positive, and
falls to zero when the AC input voltage is negative.
Full-wave rectification can be achieved
by using a bridge rectifier circuit, which uses four diodes to rectify both
halves of the AC waveform.
As you can see from the diagram, during
the positive half of the AC cycle, diodes D1 and D3 are forward biased and
conducting, while diodes D2 and D4 are reverse biased and not conducting. This
allows current to flow through the load resistance in one direction.
During the negative half of the AC cycle,
diodes D2 and D4 are forward biased and conducting, while diodes D1 and D3 are
reverse biased and not conducting. This allows current to flow through the load
resistance in the other direction.
The output of the bridge rectifier is a
pulsating DC voltage that peaks when the AC input voltage is positive or
negative.
What are some other uses for diodes?
Diodes can also be used as signal level
clippers, voltage regulators, and in power supplies where they regulate the
output voltage by clipping off the peaks of the AC waveform.
Signal level clipping is a process of
reducing the amplitude of a waveform. Diodes can be used to clip the peaks off
an AC waveform by simply connecting them in series with the load resistance, as
shown in the diagram below.
As you can see from the diagram, when the
AC voltage is positive, the diode is forward biased and conducts current. This
allows current to flow through the load resistance, and the load voltage rises.
However, when the AC voltage reaches the
diode's reverse breakdown voltage (VBR), the diode becomes reverse biased and
does not conduct. This prevents current from flowing through the load
resistance, and the load voltage falls.
The output of the signal level clipper is
a waveform with clipped peaks.
Voltage regulation is the process of
maintaining a constant voltage level. Diodes can be used to regulate the output
voltage of a power supply by clipping off the peaks of the AC waveform, as
shown in the diagram below.
As you can see from the diagram, when the
AC voltage is positive, the diode is forward biased and conducts current. This
allows current to flow through the load resistance, and the load voltage rises.
However, when the AC voltage reaches the
diode's reverse breakdown voltage (VBR), the diode becomes reverse biased and
does not conduct. This prevents current from flowing through the load
resistance, and the load voltage falls.
What are different types of diodes?
The most common type of diode is the p-n
junction diode, which consists of a p-type semiconductor material and an n-type
semiconductor material.
Other types of diodes include:
* Schottky diodes, which have a lower
forward voltage drop than p-n junction diodes and are used in high-speed
rectifier circuits.
* Zener diodes, which are designed to
operate in the reverse breakdown region and are used as voltage references or
voltage regulators.
* Light emitting diodes (LEDs), which
emit light when forward biased and are used in a variety of applications such
as indicator lights, optical fibers, and display screens.
* Photodiodes, which are used to detect
light and generate electrical signals.
Conclusion
In conclusion, diodes are essential
components in a variety of electronic circuits. They can be used to rectify AC
signals, regulate voltages, clip signal levels, and emit light. There are a
variety of different types of diodes available, each with its own unique
characteristics.
I hope you would find answers of the
following questions.
What is Diode?
What does a diode do in a circuit?
How does a diode work?
How are diodes used in rectifier
circuits?
What are some other uses for diodes?
What are different types of diodes?