What is the relationship between the light intensity of an LED and the electric current?

Below the threshold voltage: the magnitude of the current will not light up the LED above the threshold voltage:

Ideally, this is proportional, but in reality the brightness will rise at the same time due to the heat generated, but the rise rate will be lower and lower until the LED burns out.

Luminescence is the process by which electrons transition from a high-energy state to a low-energy state to release energy from photons. The voltage provides energy and will only emit light when the voltage is greater than the threshold voltage, otherwise it will not emit light.

When the voltage is greater than the threshold voltage, the current is a representation of the number of electrons provided to the high energy state per unit time, so the larger the current, the more photons can be emitted, but because the conversion efficiency (quantum effect) is not 100%, heat will be generated, and if the heat cannot be released in time, it will cause damage to the chip itself, so the current increases, the quantum effect will be reduced, and the possibility of LED burnout will increase.

LED is a current type device, and the driving mode is best to drive with constant current, and the driving voltage is only higher than the conduction voltage of the LED (generally the on-voltage of the white LED is between).

Commonly used LED lamps are 30mA, 100mA and 300mA with 1W driving currents.

The current can be appropriately smaller, which is beneficial to prolong the life of the LED, and never exceed the rated current of the LED.

The relationship between the brightness of the LED lamp and the current is shown in the following figure:

LED is the abbreviation of English Light Emitting Diode (light-emitting diode), its basic structure is an electroluminescent semiconductor material chip, cured to the bracket with silver glue or white glue, and then connected to the chip and circuit board with silver wire or gold wire, and then sealed with epoxy resin around to protect the internal core, and finally install the shell, so the LED lamp has good seismic performance. The application field involves the production of daily household appliances and machinery such as mobile phones, desk lamps, and home appliances.

Within a certain limit, the brightness increases with the increase of the current, but the brightness increases to a certain extent when the current is large, and the LED lamp is easy to age, or even burn out.

The voltage of LED, white, green, and blue light is generally calculated, and the red and yellow light are calculated according to 2V.

If it is a small power, such as a straw hat type or bullet type, the current is calculated as 20mA, if it is a high power of 1W, the maximum current is 350mA, and the current of 3W is 700mA

If the lamp beads are connected in series, the voltage is added and the current is not changed, and if they are connected in parallel, the voltage is unchanged and the current is added.

For example, the working voltage of an LED light-emitting tube, the rated current, and the measured power supply +12V, are (ohms.

It is best to find the instruction manual of the chip that encapsulates the light source, and calculate the voltage and current of the power supply according to the series mode of the combined circuit according to the above introduction.

There is no manual, so I have to connect the power supply to the voltage and current source, start from a small and increase it, until the light source is the brightest.

When the frequency of incident light can excite the photocurrent, the intensity of the photocurrent is basically proportional to the intensity of the light source for the first period of time.

Next, as more and more electrons on the surface of the metal become free electrons due to the energy level transition, the intensity of the photocurrent gradually decreases to zero. In this process, the relationship between the intensity of the photocurrent and the intensity of the light source is not linear.

Yes, the stronger the intensity of the irradiated light, the greater the photocurrent.

Whether or not photocurrent is generated depends on the frequency of irradiated light, these two concepts are easy to confuse.

Luminous flux, in general, is the total amount of light emitted by a light source (or lamp) and is measured with an "integrating sphere".

Luminous intensity, i.e., light intensity i, is theoretically the luminous flux emitted by a point light source in a certain direction, per solid angle. If it is an ideal uniform point light source, then the relationship between the two is i = 4.

Since LEDs only emit light forward, and the light emitted at different angles is non-uniform, it is difficult to convert them to each other.

For LED lights for lighting, luminous flux should be used. For the display, the light intensity directly in front of it should be used.

It is said that it can be converted directly, but few people know about it. We can test both of them, the national testing laboratory, please call the user name below to contact me, my name is Tang Ting.