2024-01-03
Selection method of working voltage and current limiting resistance of low power LED lamp bead
The application of low power LED lamp beads in some special occasions can not be replaced, this article will introduce the working voltage and current limiting resistance of various colors of low power LED lamp beads.
Various colors of small power LED lamp bead working voltage.
The above figure shows the working voltage of the low-power LED in various colors. The maximum operating current of these leds is generally 20mA (exceeding this value will not necessarily be damaged, but will shorten the use time of the LED). For low-power LED with ordinary brightness, the actual working current is generally 5 ~ 15mA; For high brightness LED generally take 1 ~ 5mA. Among them, the working voltage of red LED is 1.5 ~ 1.6V, the working voltage of green ordinary brightness LED is about 1.8V, the working voltage of yellow LED is 1.8 ~ 2.0V, and the working voltage of white and blue LED is 3.0 ~ 3.3V.
Calculation method of low power LED current limiting resistance.
For the above colored low-power LED, the use of the method is very simple, as long as the series of a suitable resistance value of the current limiting resistance can be lit. The following describes the calculation method of low power LED current limiting resistance.
Assuming that the power supply voltage of the LED is 5V, the LED used is a green LED with ordinary brightness and positive voltage drop of 1.8V, and the working current is 10mA, then the current limiting resistance R = 5V-1.8V/10mA = 0.32KΩ (that is, 320Ω). Since there is no resistance with a nominal value of 320Ω in the common resistors, a resistance with a nominal value of 330Ω is selected. Because the current flowing through the current limiting resistor R is only 10mA, R can choose a ¼W metal film resistor.
Assuming that the power supply voltage of the LED is 5V, the LED used is a green LED with ordinary brightness and positive voltage drop of 1.8V, and the working current is 10mA, then the current limiting resistance R = 5V-1.8V/10mA = 0.32KΩ (that is, 320Ω). Since there is no resistance with a nominal value of 320Ω in the common resistors, a resistance with a nominal value of 330Ω is selected. Because the current flowing through the current limiting resistor R is only 10mA, R can choose a ¼W metal film resistor.
Green high brightness LED.
Commonly used green high-brightness LED, the working voltage of this LED is large, generally around 2.2V, and some are even larger. Due to the high luminous efficiency of this LED, it is used as an indicator, and the working current is 1 ~ 3mA, which is very bright.
