Simple USB Reading Lamp Circuit

A USB reading lamp circuit is like a tiny power plant for your reading book.

It lets you build a small, portable lamp that gets its juice from any USB port on your computer, laptop or even a power bank.

These little lamps are perfect for casting some light while you curl up with a good book or for adding some extra illumination to your workspace.

The circuit itself is pretty simple, using LEDs, resistors and sometimes even a special voltage regulator to make sure the light is just right.

So ditch the bulky lamps and grab your USB cable it is time for some DIY reading light fun.

Circuit Working:

Parts List:

Illuminate your tabletop with this stylish white LED Lamp.

Designed to be powered from a USB port, it is perfect for taking notes while browsing the internet.

The USB port provides 5V and 100mA current, ample for lighting the LED lamp.

The circuit draws power from the USB port via a standard A type plug.

Zener regulation is employed to ensure continuous regulated power.

Resistor R1 limits the base current to T1 ensuring current regulation in the output.

A 4.7V zener is used to provide a constant 4.7V to the LEDs meeting the minimum 3.6V required by white LEDs.

Resistor R2 limits the LED current to around 20mA to prevent damage.

Connect the power lines to the USB plug observing the correct polarity.

For maximum illumination use a reflector for the LEDs.

Formula:

Below is the formula for component LED for USB Reading Lamp Circuit:

Current Limiting Resistor RLED:

Utilizing ohms law, determine the resistor value R_LED for every LED.

R_LED​ = ​V_USB ​− V_LED​​ / I_LED

where:

• V_USB​ is the USB supply voltage around 5V.
• V_LED​ is the forward voltage drop of the LED.
• I_LED​ is the desired current through the LED i.e 20mA.

Note:

You may create a circuit for a USB reading lamp that effectively powers white LEDs from a USB port by utilizing these formula and recommendations.

Depending on the required brightness and the particular LED characteristics, adjust the component values.

To guarantee correct operation, thoroughly test the circuit and make any necessary adjustments for best results.

How to Build:

To build a Simple USB Reading Lamp Circuit following are the steps mentioned below:

Assembly Steps:

Prepare the USB Cable:

• Cut the USB cable and strip the insulation to expose the power and ground wires.

Solder Components:

• Solder the components LEDs, Zener diode, transistor, resistors onto the PCB according to the circuit diagram.
• Place the components close together to minimize wire lengths.

Connect Components:

• Wire the components together according to the circuit diagram.
• Ensure the polarity of the LEDs and Zener diode is correct.

Connect USB Cable:

• Solder the power and ground wires of the USB cable to the circuit observing correct polarity.

Test the Circuit:

• Connect the USB cable to a power source such as a computer or USB wall adapter and test the circuit.
• The LEDs should light up evenly.

Safety Precautions:

• Ensure the circuit is properly insulated and secured to prevent short circuits.
• Use heat sinks when soldering to protect components from heat damage.
• Avoid touching the soldering irons tip directly.
• Work in a well ventilated area to avoid inhaling solder fumes.

Conclusion:

A USB reading lamp circuit is a basic and cost effective project for creating a portable light source powered by a USB port.

By using basic electronic components like LEDs, resistors and possibly a transistor and zener diode you can build a functional lamp suitable for reading or providing additional lighting in various settings.

This project offers a practical way to learn about electronics while creating a useful and versatile device.

References:

USB-Powered PC Lamp