USB Circuit Diagrams

USB LED Lamp Circuit

In this project, I will demonstrate how to construct a straightforward circuit. This circuit is a basic DIY USB LED Lamp that can provide supplementary lighting for your laptop or tablet computer.


  • Introduction 
  • USB LED Lamp Circuit Diagram
  • USB LED Lamp Circuit Design
    • USB LED Lamp Circuit Simulation Video
  • How to Design the USB LED Lamp Circuit?
  • How to Operate USB LED Lamp Circuit?
  • USB LED Lights Circuit Advantages
  • Applications of USB LED Lamp Circuit


Universal Serial Bus (USB) is commonly known as USB, which stands for Universal Serial Bus. The USB standard was introduced to simplify the process of connecting various devices to a computer. In fact, the USB port has become the standard interface for connecting a wide range of external devices, including keyboards, mice, printers, DVD writers, hard disk drives, and more.

Please note that in this project, we are referring to a generic USB port, as it serves as the basis for our design.

Now, let’s consider the project itself. There are situations where you might struggle to see the keyboard keys clearly due to poor lighting conditions or power outages (especially if you don’t have a backlit keyboard). What if there was a convenient way to address this issue? That’s where a USB-powered lamp circuit comes into play.

Since the USB port provides a 5V output, it can be effectively utilized to power a simple LED lighting circuit. Additionally, this USB-powered LED lamp offers the advantage of eliminating the need for bulky lamps, as it provides a compact and portable solution to enhance your workspace lighting.

USB LED Lamp Circuit Diagram

Circuit Components

  • USB Male Connector
  • Light Emitting Diodes – 5 X 5mm White LEDs
  • Resistors – 100Ω X 5
  • Perf Board

USB LED Lamp Circuit Design

The primary component of the circuit is a male USB connector. USB connectors are typically categorized into two types: Type ‘A’ and Type ‘B’. These USB connectors come in various shapes, each designed for specific purposes. Type ‘A’ USB connectors are commonly used by upstream devices like USB hubs or hosts, while Type ‘B’ USB connectors are typically found on downstream devices such as printers.

It’s worth noting that even though USB cables may have the same number of pins, their physical designs can differ. Over the years, several USB versions have been introduced. The initial USB 1.0 and 1.1 versions had a data transfer rate of 12 Mbps. USB 2.0, on the other hand, offers a significantly higher data rate of 480 Mbps. USB 3.0 is capable of achieving a projected data rate of 4.8 Gbps.

Do you know anything about the 3X3X3 LED Cube Circuit?

The type of USB utilised here is ‘A’. There are four pins on it. VCC, GND, D+, and D- are the pins in question. The data pins are the D+ and D- pins. The VCC pin generates a voltage of 5V. The USB LED Lamp with Type ‘A’ male USB connector may simply be plugged into a computer’s USB port.

A two-lead LED is a semiconductor device. LEDs were originally used for indicating, but they are increasingly becoming the primary source of illumination in homes, offices, streets, autos, and other places. A typical P-N junction diode is similar to an LED. The energy emitted is in the form of light when applied with the required voltage, while normal P-N junction diode emits energy in the form of heat.


The hue of light emitted is determined by the semiconductor’s band gap. The LEDs used in this project are standard white LEDs. They feature a 3.6V voltage drop. The LEDs require a current of 40mA. Initially, these LEDs were only available in red; however, high-power LEDs and other coloured LEDs, such as blue LEDs and white LEDs, were created subsequently.

NOTE: The forward voltage and current numbers should be found on the LED’s data sheet.

Between the Light Emitting Diode and the USB lies a 100 ohm resistor. This resistor serves as a current limiter. Because LEDs require a maximum current of 40mA to operate at full brightness, they must be protected from currents greater than this.

As a result, a resistor between the LED and the power source should be used to limit the amount of current passing through the LED. The current drop at the Light Emitting Diode is 40 milli amperes, while the supply voltage from the USB is 5V. The resistor value can be calculated using the formula below.

where, the value of V is 5 volts and the value of I is 40 mA.

So, R= 5V/0.04A =125 ohms

But generally, 125 ohm resistor does not exist in real time. Therefore a resistor of 100Ω is used instead of 125Ω. Though it gives an output current of 50 mA, this can be tolerated by the LED.

USB LED Lamp Circuit Simulation Video

How to Design the USB LED Lamp Circuit?

Take a small piece of perf board and solder the Male USB Connector. Then start soldering the LEDs and 100Ω Resistors. Scrape the edges to smoothen the perf board.

How to Operate USB LED Lamp Circuit?

  • Initially connect the circuit as shown in the circuit diagram.
  • Now insert the USB to the port of the computer.
  • You can observe the lamp glowing
  • Now remove the USB from port.
  • Now lamp is switched off.

USB LED Lights Circuit Advantages

  • This is simple and inexpensive.
  • This is a portable lamp.
  • No extra source is required.

Applications of USB LED Lamp Circuit

  • This can be used as a flashlight in an emergency. Get a sense of how the Automatic LED Emergency Lights Circuit works.
  • This can be used to work on a laptop or computer while the rest of the family sleeps.
  • This lamp can also be used as a reading light.

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