LED Characteristics Apparatus
Product Code : SCL-EAE-11171
Quick answer: The LED Characteristics Apparatus is used to study how the current through a light-emitting diode changes as the forward voltage is increased. Students record voltage and current, plot the V-I curve and find the voltage at which the LED starts to conduct and glow. Lab Exports manufactures it in Delhi for schools, colleges, universities and technical training laboratories.
Specifications
| Parameter | Detail |
|---|---|
| Principle | Voltage-current characteristics of a light-emitting diode |
| Measured quantities | Voltage and current |
| Concepts covered | LED behaviour, forward bias, semiconductor characteristics, V-I curve |
For the number and colours of LEDs, the meters and the power arrangement, email [email protected] with the house code SCL-EAE-11171.
How the LED characteristics experiment is done
An LED is a PN junction diode made from a semiconductor that emits light when electrons and holes recombine at the junction. Like any diode it passes almost no current in forward bias until the applied voltage reaches its threshold, or knee, voltage; above that, the current rises steeply and the LED glows. The knee voltage depends on the semiconductor, which is why red, green and blue LEDs switch on at different voltages.
- Connect the LED in forward bias with a series current-limiting resistor, a voltmeter across the LED and a milliammeter in series.
- Start from zero and raise the voltage in small steps.
- Record the voltage and current at each step, noting when the LED first glows.
- Stop before the current exceeds the LED's safe limit.
- Plot current against voltage and read off the knee voltage.
The knee voltage links electronics to modern physics: the energy of the emitted photons is roughly e x V, so equating it to hc/lambda gives an estimate of Planck's constant when the LED's wavelength is known.
Key features
- Demonstrates the forward-bias V-I characteristic of an LED.
- Visible light output shows when conduction begins.
- Supports recording of voltage and current data and plotting of the characteristic curve.
- Helps explain forward bias, threshold voltage and semiconductor behaviour.
- Suited to teacher demonstrations, student practicals and electronics training.
Documentation and supply
Most Lab Exports products carry a one-year manufacturer warranty.
Lab Exports manufactures the LED characteristics apparatus at its works in Laxmi Nagar, Delhi, and supplies it to schools, colleges, universities and technical training laboratories in India and 60+ countries, handling the export documents for each shipment. More about the company is on the About Lab Exports page.
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The full range is in the Electrical and Electronics section of the Physics Lab range.
Frequently asked questions
What is the knee voltage of an LED?
It is the forward voltage at which the LED begins to conduct significantly and emit light. It depends on the semiconductor material, and so on the colour of the LED.
Why is a series resistor used in the LED experiment?
Above the knee voltage the LED current rises very steeply, so a series resistor limits the current and protects the LED.
What is the price of the LED characteristics apparatus?
Prices are not published on the website. Add the LED characteristics apparatus to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code SCL-EAE-11171 and the quantity, to receive a quotation.
Does Lab Exports manufacture the LED characteristics apparatus?
Yes. Lab Exports manufactures the LED characteristics apparatus at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code SCL-EAE-11171.
Request a quote
Email [email protected] with the house code SCL-EAE-11171 and the quantity, or add the LED characteristics apparatus to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.
