Last updated on March 19th, 2024 at 01:35 pm
1N4148 diode is a standard signal P-N junction diode. It has a medium voltage drop of 0.72 V and a low current rating of 300mA.
Hence, this diode is mainly used for general operations like fast switching, high-speed rectification, and protection of telecommunication devices.
In this post, we will learn the basics of this diode.
Table of Contents
What is a 1N4148 diode?
1N4148 is a type of switching diode. These diodes provide quick switching (up to about 100 MHz) and are popularly used in low-current applications. This switching diode was first registered at JEDEC in 1968 for military and industrial applications.
Due to its small size, low cost, and easy availability, it is now the most commonly produced switching diode, replacing the former 1N914 diode.
Features of 1N4148 diode
- The maximum current carrying capacity is 300mA.
- Its recovery time is 8ns.
- The power dissipation rating for this device is up to 0.5mW.
Modes of operation
The diode works similar to a signal diode allowing current flow in a single direction, i.e., from Anode to Cathode. Depending on the way it is connected across a voltage source, there are two modes of operation: Forward and Reverse bias.
Forward biased mode: Diode works like a closed switch and allows the current to flow through it.
Reverse biased mode: Diode works as an open switch and does not allow the current flow.
Below a specified voltage (cutoff voltage), the diode shows high resistance while above that specific voltage, it shows low resistance.
1N4148 diode pinout
Given below are the pins of all 1N4148 variants for easy identification.
| Pin No. | Pin Name | Polarity | Function |
| 1 | Anode | Positive | The current enters through the Anode |
| 2 | Cathode | Negative | The current exit through the cathode. |
Specifications
The specifications like the operating voltage, and working temperature range for the diode are provided in the table below.
| Parameter | Value |
| Package | SMD and DO-35 |
| Diode type | Fast switching Diode |
| Peak repetitive reverse voltage | 100V |
| Working temperature range | (-65°C to 175°C ) |
| Power Dissipation | 500 mW |
| Peak forward surge current | 2A |
| Forward continuous current | 300mA |
| Reverse recovery time | 8ns |
What are the equivalents of 1N4148?
So, if are looking for an alternative to 1N4148, you can use these diodes:
- 1N914
- 1N916/1N4149
- 1N4446/1N914A
- 1N4447/1N916A
- 1N4448/1N914B
- 1N4449/1N916B
What is 1N4148 diode used for- Applications
It is your go-to diode when it comes to normal use. You can use it in digital logic circuits, in power supplies due to its fast switching capability and quick recovery time.
It is sometimes used in rectifier circuits where operating voltages are less than 100 V. Although 1N4007 is a better alternative due to its higher reverse voltage ratings.
Some applications of 1N4148 where it is commonly used are as follows:
- Digital logic circuits
- General and high-speed switching
- Signal filtering
- Rectification
- In different circuits like power supply, voltage double, and battery charger circuits.
- Protection circuits in telecommunication industries, offices, homes, etc.
Datasheet(TH and SMD)
1N4148 is available in three types: Axial lead, bolt mount, and Surface mount type.
To download the datasheet of Axial lead through-hole 1N4148 diode, click here.
To download the datasheet of Surface mount 1N4148 diode, click here.
FAQs
Is 1N4148 a Zener diode?
No, 1N4148 is not a Zener diode. Although it looks like a Zener diode, it is a normal diode. While a Zener diode is mostly used as a voltage regulator, this is used in fast-switching applications.
What is the voltage of diode 1N4148?
It has a peak repetitive reverse voltage rating of 100V.
What is the maximum power of 1N4148?
The maximum power dissipation rating of the diode is 500mW.
How do I identify a 1N4148 diode?
To identify a 1N4148 diode, look for a small glass case with a black band. This band marks the negative side (cathode). The diode might also be marked “1N4148” or a shorter version.
