As a supplier of 5mm Ir Leds, I understand the importance of accurately measuring the parameters of these components. In this blog post, I will share some insights on how to measure the key parameters of 5mm Ir Leds, which can help you ensure the quality and performance of your products.
1. Forward Voltage (Vf)
The forward voltage is the voltage drop across the LED when it is conducting current in the forward direction. To measure the forward voltage of a 5mm Ir Led, you will need a power supply, a current - limiting resistor, and a multimeter.
First, set up the circuit. Connect the positive terminal of the power supply to one end of the current - limiting resistor, and the other end of the resistor to the anode of the 5mm Ir Led. Connect the cathode of the LED to the negative terminal of the power supply. The current - limiting resistor is used to prevent excessive current from flowing through the LED, which could damage it.
Calculate the value of the current - limiting resistor using Ohm's law. The formula is (R=\frac{V - V_f}{I}), where (V) is the supply voltage, (V_f) is the expected forward voltage of the LED (usually around 1.2 - 1.5V for infrared LEDs), and (I) is the desired forward current (commonly 20mA for 5mm Ir Leds).
Set the power supply to a voltage that will allow the desired current to flow through the LED. For example, if you want a forward current of 20mA and assume a forward voltage of 1.3V, and your power supply voltage is 5V, then the value of the resistor (R=\frac{5V - 1.3V}{0.02A}=185\Omega). You can use a standard resistor value close to this, such as 220Ω.
Connect the multimeter in parallel with the LED. Set the multimeter to measure DC voltage. Turn on the power supply, and the multimeter will display the forward voltage of the 5mm Ir Led.
2. Forward Current (If)
The forward current is the amount of current flowing through the LED in the forward direction. Measuring the forward current is relatively straightforward.
Using the same circuit setup as for measuring the forward voltage, connect the multimeter in series with the LED. Set the multimeter to measure DC current. When you turn on the power supply, the multimeter will show the forward current flowing through the LED.
It is important to note that exceeding the maximum forward current specified by the manufacturer can significantly reduce the lifespan of the LED or even cause it to fail. Therefore, always ensure that the forward current is within the rated range.
3. Radiant Intensity (Iv)
Radiant intensity is a measure of the amount of infrared radiation emitted by the LED in a particular direction. Measuring radiant intensity requires specialized equipment, such as a photodetector and a power meter.
A common method is to use a calibrated photodetector. Place the 5mm Ir Led at a fixed distance from the photodetector, usually 1m. The photodetector converts the infrared radiation it receives into an electrical signal, which can be measured by a power meter.
The radiant intensity is calculated based on the power measured by the power meter and the solid - angle subtended by the photodetector at the location of the LED. The formula for radiant intensity (I_v=\frac{\Phi}{\Omega}), where (\Phi) is the radiant flux (power) and (\Omega) is the solid - angle.
However, for most practical purposes, you can use a pre - calibrated measurement setup provided by the equipment manufacturer. This setup will directly give you the radiant intensity value of the 5mm Ir Led.
4. Peak Wavelength ((\lambda_p))
The peak wavelength is the wavelength at which the LED emits the maximum amount of infrared radiation. Measuring the peak wavelength requires a spectrometer.
A spectrometer works by dispersing the light (in this case, infrared light) emitted by the LED into its component wavelengths. The spectrometer then measures the intensity of the light at each wavelength.
To measure the peak wavelength of a 5mm Ir Led, place the LED in front of the spectrometer's input port. Turn on the LED, and the spectrometer will scan the wavelengths and record the intensity at each point. The wavelength at which the intensity is maximum is the peak wavelength.
Typical peak wavelengths for 5mm Ir Leds range from 850nm to 940nm. Different applications may require different peak wavelengths. For example, 850nm is often used in security cameras, while 940nm is more suitable for applications where visible light interference needs to be minimized.
5. Viewing Angle
The viewing angle of a 5mm Ir Led refers to the angle within which the LED emits a significant amount of infrared radiation. Measuring the viewing angle can be done using a goniometer and a photodetector.
Mount the 5mm Ir Led on the goniometer, which allows you to rotate the LED around a fixed axis. Place the photodetector at a fixed distance from the LED, for example, 1m.
Start with the LED facing the photodetector directly (0 - degree angle). Measure the radiant intensity using the photodetector and power meter setup described earlier. Then, slowly rotate the LED using the goniometer and measure the radiant intensity at different angles.
The viewing angle is usually defined as the angle at which the radiant intensity drops to half of its maximum value. For example, if the maximum radiant intensity is measured when the LED is facing the photodetector directly, and the intensity drops to half of this value at an angle of (\pm 30^{\circ}), then the viewing angle is (60^{\circ}).
Why Accurate Parameter Measurement Matters
Accurately measuring the parameters of 5mm Ir Leds is crucial for several reasons. Firstly, it ensures that the LEDs meet the required specifications for your application. For example, if you are using 5mm Ir Leds in a security system, the radiant intensity and peak wavelength need to be within a certain range to ensure proper detection.
Secondly, it helps in quality control. By measuring the parameters of each batch of LEDs, you can identify any defective or out - of - spec components and take appropriate actions, such as rejecting the batch or adjusting the manufacturing process.
Finally, accurate parameter measurement allows for better system design. You can optimize the performance of your products by selecting LEDs with the most suitable parameters.
Our Product Range
As a supplier of 5mm Ir Leds, we offer a wide range of products to meet different customer needs. Our 5mm Infrared LED Emitters are known for their high quality and stable performance. We also provide 3mm Infrared Lamp LED Emitters for applications where space is limited. In addition, our 0.5W IR LED is suitable for applications that require higher power output.
Contact Us for Procurement
If you are interested in purchasing our 5mm Ir Leds or any other infrared LED products, we welcome you to contact us for procurement and further discussions. Our team of experts is ready to assist you in selecting the most appropriate products for your specific requirements. Whether you need a small quantity for prototyping or a large - scale order for mass production, we can provide you with competitive pricing and reliable delivery.
References
- "LED Handbook" by LED Industry Association
- "Optoelectronics: An Introduction" by John Wilson and Jim Hawkes