1N4148 Diode : Pin Configuration & Its Applications

A diode is a two-terminal component that allows the flow of current only in a single direction from the Anode to the cathode. Here, the identification of the cathode terminal can be done with the help of a grey bar. We know that there are different types of switching diodes that are used for switching purposes in different applications like 1N4007 diode, 1N4148 diode, etc.


For this IN4148 Diode, the maximum capacity for carrying current is 300mA & it can resist up to 2A. This diode has 8ns of quick recovery time at 10mA of a forward current; so this diode is applicable where fast switching is required. So, this article discusses an overview of a 1N4148 diode like pin configuration, specifications, circuit, and its applications.

What is a 1N4148 Transistor?

1N4148 diode is mainly used for quick switching purposes, so these are known as switching diodes. The main functionality of these diodes is the same as a normal switch. These diodes have high resistance under a fixed voltage whereas they have low resistance above the fixed voltage.

1N4148 Diode
1N4148 Diode

This kind of diode is easily available in a tiny size with less cost. So the selection of this diode can be done based on its highest reverse recovery time as well as its power dissipation that ranges from 80milli Watts to 1kilo Watts.

It is frequently used in different switches which have a very quick operation for switching, high-speed rectification, protection of homes & telecommunication industries, etc.

Pin Configuration

The pin configuration of the 1N4148 diode is shown below. This diode includes two pins where each pin is discussed below.

1N4148 Diode Pin Configuration
1N4148 Diode Pin Configuration
  • Pin1 (Anode): This pin allows the flow of current
  • Pin2 (Cathode): The flow of current exists from this pin

Features & Specifications

The features and specifications of the 1N4148 diode include the following.

PCBWay
  • It is available in SMD & DO-35 packages
  • Max temperature ranges from -65 C to +175 C
  • Si epitaxial quick switching diode
  • Recovery time in reverse is 8ns
  • Power dissipation max is 5W
  • Max forward surge current is 2A
  • Reverse voltage is 75V
  • Usual rectified current (max) is 15A/150mA
  • Reverse voltage with repetitive (max) is 100 V

Equivalent and alternative 1N4148 diodes are 1N914, 1N914B, IN914A, 1N916A, 1N916, 1N916B, 1N4448WS, 1N4448, 1N4148WS & 1N4448W.

The main characteristics of the 1N4148 diode are; it is a flexible high-frequency-based switching diode. Its packages mainly include DO-35, DO-14, SOD123, LL34, SOD323, SOT23, SOD523, 0805, etc. The specifications which are mentioned above will make to use in different applications. So, these are very simple to use, versatile & inexpensive.

1N4148 Diode Modes of Operation

1N4148 diode is a typical diode designed with a silicon material, used especially for fast switching operations. The operation of this diode can be done in two modes like forward biased & reverse biased.
In forward bias operation mode, it permits the flow of current throughout it & performs like a closed switch, whereas in reverse biased mode this diode works like an open switch by not allowing the flow of current throughout it.


In this circuit, LED is used as a load. In forward bias mode operation, the IN4148 diode acts like a closed switch by allowing the flow of current through the LED. So it will turn ON.

Similarly, in reverse bias mode operation, this diode works like a closed switch so there is no flow of current throughout an LED, so it will turn OFF. The equivalent circuits of both the states of the diode are shown above.

How to Run 1N4148 Diode Safely within a Circuit?

In electronics projects, to perform 1N4148 diode for the long term then it is suggested to verify the mark on the cathode terminal of the diode, connect it in the correct polarity within the circuit. As per the defined specifications above, we should not provide high voltage & current. We always need to operate & store within temperature >-65 C & < +175C

How to use 1N4148 Diode?

The circuit diagram of the temperature sensor using 1N4148 diode is shown below. There are different electronic components available that have special features. From them, 1N4148 diode is one of the components because it is a high-speed diode with 100 V & 450 mA of current and its speed of switching is 4th. In this circuit, 1n4148 diode is used as the temperature sensor due to many characteristics. These characteristics will change along with the change in temperature.

The required components of this circuit are resistors 1.5K, 15k, variable resistors VR1 & VR2 – 10K, IC741, 1N4148 diode, ZD1 – 5.6v.

1N4148 Diode Circuit
1N4148 Diode Circuit

Obviously, it does not contrast with a sensor, however, for some electronic circuits which are used for low precision, which just require identifying if an element is cold or hot it is very useful. The above circuit measures the temperature in an easy way with the help of a multimeter.

This circuit utilizes a 1N4148 diode & both the variable resistors like VR1 & VR2 should be regulated through a thermometer & it is a more accurate measurement. On the multimeter scale, it can be evaluated to the degree Celsius scale through Volt.

Where to use 1N4148 Diode/Applications

The applications of 1N4148 diode include the following.

  • 1N4148 diode is used in different electronics applications where AC to DC making is required.
  • It protects different electronic components from damage by blocking voltage spikes
  • This type of diode is used in digital logic circuits.
  • General & high-speed switching
  • Protection of components
  • Rectification
  • Signal filtering
  • It blocks incoming voltage wherever not necessary
  • It is also used in different circuits like power supply, voltage double & battery charger circuits.

1N4148 diode is a high-speed switching diode with small size and fast switching. Its applications mainly include single supply isolation for high-frequency signal circuits, industrial control circuits, computer boards, communication, TV, etc.

Thus, this is all about an overview of the 1N4148 diode datasheet which includes its pin configuration, features, specifications, circuit, characteristics, and applications. This 1N4148 diode is a typical Si switching signal diode and one of the most famous & long-lasting diodes due to its reliable specifications as well as less cost. This diode is extremely useful within switching applications equal to 100 MHz through a reverse-recovery time not above 4 ns. Here is a question for you, what are the different types of switching diodes available in the market?

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