# Rectifier vs Zener vs Schottky Diode(Practical Differences)

A diode is a passive device that allows the flow of current in one direction only. But since there are so many types of a diode, it’s important to differentiate between them. And to know which one to use according to its requirement in our circuit. Given below is a detailed difference between diode, Zener diode, and Schottky Diode.

So in this post, we are going to see the basic difference between the three most widely used diodes: rectifier, Schottky, and Zener diode and when to use one.

Watch this video for quick reference:

Before jumping to a specific diode type, let’s look at some of the basic characteristics of a diode.

## Basic Characteristics of a Diode:-

 Diode’s Property Definition Vf It indicates the forward voltage drop when current flows from the P to N terminal of the diode. If It is the maximum fwd current a diode can handle VR It is the reverse break down voltage when current flows from N to P terminal. IR The amount of current that flows when a diode is reverse biased. tRR When a diode is switched off suddenly, the fwd current flowing through the diode takes a small amount of time to die down and this time is called Reverse Recovery Time.

## RECOVERY TIME of a Diode:

When a diode is switched off suddenly, the fwd current flowing through the diode takes a small amount of time to die down. This time is called Reverse Recovery Time

## Difference between diode, Zener diode, and Schottky Diode:

Now let’s study diode’s type one by one:

### 1. Rectifier Diode:

• A rectifier diode is the simplest p-n junction diode, used mostly for rectification purposes in a half-bridge and full-bridge rectifier. And that’s because of its high break down voltage, typically of the order of 200 to 1000 volts which is obvious.
• The forward voltage drop (Vf) of a rectifier diode is between 0.7 to 0.9 volt.
• As an example, let’s say you want to design a bridge rectifier for your ac to dc converter project. For this bridge rectifier, the diode of the 1N4 rectifier series is an optimum choice.

### 2. Schottky Diode

• Unlike a rectifier diode, the junction of a Schottky diode is between an n-type semiconductor and a metal plate.
• Schottky diode, also known as barrier diode is mainly used in low voltage circuits because the forward voltage drop of Schottky diode(Vf) is less than a rectifier diode. Typically in the range of .25 to .5 v.
• In a Schottky diode, electrons are the majority charge carriers on both sides of the junction. Thus it is a unipolar device.
• It is mostly used in high-frequency applications like in an SMPS. And that’s because of less temperature rise and high switching speed pertaining to its small recovery time.

• One disadvantage of Schottky diode is its low breakdown voltage ( 20v to 40v ) making it unsuitable for a rectifier circuit.

Note: Compared to a normal rectifier diode, the reverse recovery time of a Schottky diode is much smaller. This makes it suitable to be used in fast switching circuits.

• As an example, let’s say we are designing a buck converter as we did in one of the project videos: “Buck converter using Arduino“.
• Since Mosfet in this circuit is switching with a very high frequency, the diode you need in this circuit should have a high switching speed. Thus Schottky diode is an optimum choice.

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### 3. Zener Diode:

• Zener diode is made up of a p-n junction but is heavily doped compared to a normal diode. As a result, it can undergo breakdown without being damaged.
• And due to this property only, the Zener diode is used as a voltage regulator in electronic circuits.
• In fact, Zener diodes are never used for rectification purposes.

What is a Voltage Regulator

• Here’s a circuit in which a Zener diode is used to prevent the MOSFET gate from destruction by clipping off input voltage. The breakdown voltage of this Zener is 5.1 v.