How do you know how many volts is designed LED

Of course, we all know that the main parameter of the LEDs is the rated current. But in addition, it is also very important to know at what voltage rated LED.

I hasten to say that the acronym refers to the LED voltage potential difference in the p - n transition in the open state. This option is for reference only and can be found in the technical documentation, which is also indicated, and other parameters of the LEDs.

But often we do not have at hand the documents to the LED, which we found in his reserves. But how do you know the voltage drop in this case, we'll talk in the article.

We determine the theoretical voltage drop method

So, you have a LED, but there is no documentation on it. Color LED lights that can tell you a lot, as the body itself, the shape and size of the semiconductor device.

If the LED housing transparent compound, in what color it glows without mystery connection. To determine and simultaneously check the serviceability of LED, we need a multimeter.

Translate switch to continuity and diode test probes touch alternately conclusions. In this case, the working LED in forward bias, you will see that it is slightly light up.

In this simple way you have defined the color and condition of the LED.

Why is it important color of light? Yes, everything is simple. LEDs of different colors are made of different semiconductors. That semiconductor chemistry largely determines what the voltage drop will be at the P-N junction.

But as in the time of production is used a lot of chemical elements, only the color can be determined only approximately a voltage of a particular LED is designed.

If you know the color of your LED, it is possible to find in the Internet the technical documentation for LEDs similar design, but necessarily the same color. And in her view about what voltage your LED.

Theoretical research you will be able to give only approximate figures, but practical experience will determine the actual voltage of the LED.

The practical definition of the LED voltage

To determine the voltage in practice except for the LED need another resistor with resistance of 580 ohms (possible) regulated power supply, e.g. like mine.

We are putting all our details here on this circuit:

It's all very simple: via a resistor we limit the current, and we multimeter control the forward voltage drop across the LED.

And checking is as follows: from the power source smoothly adjustable (from zero) begin supplying power. Once its value will be selected to trigger threshold, the LED will light up.

With further increase in the brightness voltage reaches its nominal value and the testimony of a multimeter (in the voltmeter mode) will cease to grow. This would indicate that the p - n junction is fully open and a further increase in voltage on the power supply to be applied exclusively to the resistor.

These are the indications on the multimeter and point to the rated forward voltage of the LED.

Note. If you see that on the multimeter Set the voltage of 1.9 volts, but the LED does not light up, it is likely that in front of you an infrared LED. To see this, take the phone, turn on the camera and look at the test LED through it. If you see that the camera it glows brightly, it means that you are testing is an infrared LED.

conclusion

That is such a simple way you can find the voltage of the LED. If you liked the article, you will appreciate it Like. Thank you for your attention!