The IO port of a general chip allows a higher input current than its output current, so it is usually connected in the form of a pull-up resistor. In addition, since the forward volt-ampere characteristic curve of the LED is steep, a current limiting resistor should be connected in series when applied. The LED cannot be directly connected to the power supply to avoid burning the LED and damaging the microcontroller.
2. Calculation method of series current limiting resistor
R= (Vcc-Vz)/Iled; Vz is the voltage drop of the LED, and Iled is the working current of the LED.
3.
Different LED parameter materials have different forward voltage drops:
the forward voltage of gallium phosphide LEDs that emit red and green light is 2.3V. There is also a forward voltage of 1.5-1.7V for red-light gallium arsenide phosphide LEDs.
Generally speaking, it is judged by color:
The forward voltage drop of yellow-green (565-575nm), yellow (585-595nm), and red (600-650nm) LEDs is 1.8-2.4V, with an average of 2.0V.
The forward voltage drop of blue (465-475nm), green (500-535nm), and white LEDs is between 2.8-4.0V, and is generally 3.3V.
4. The maximum current sink of the PIC microcontroller pin is 25mA
Previous article：STC12C MCU PWN Control
Next article：STM8L152 simulation IIC program
- Popular Resources
- Popular amplifiers
TS27M2BMPT
- Learn ARM development(19)After many days of hard work, I finally got the interrupt working. But in order to allow RTOS to use timer interrupts, what kind of interrupts can be implemented in S3C44B0? There are two methods in S3C44B0. ...
- Learn ARM development(14)Since development under LINUX is still quite troublesome, is there a more convenient and simple development method under WINDOWS? The answer is yes. Of course, it is not a development tool like ADS, because it ...
- Learn ARM development(15)When using GCC to develop ARM, you will definitely encounter compiler problems. For example, you will encounter various warnings and errors when compiling C code. For example, I encountered several warnings yesterday, so let's take a look at what these warnings are ...
- Learn ARM development(16)There are many things to learn about ARM, and interrupts are definitely something that needs to be learned. Since the CPU introduced interrupts, it has truly entered the multi-tasking system and greatly improved work efficiency. ...
- Learn ARM development(17)Because all embedded systems use interrupts, how does my S3C44B0 interrupt the process? Then I need to understand the whole process. To understand it in depth, the best way is to write a program ...
- Learn ARM development(18)
- Embedded system debugging simulation tool
- A small question that has been bothering me recently has finally been solved~~
- Learn ARM development (1)
Professor at Beihang University, dedicated to promoting microcontrollers and embedded systems for over 20 years.
- LED chemical incompatibility test to see which chemicals LEDs can be used with
- Application of ARM9 hardware coprocessor on WinCE embedded motherboard
- What are the key points for selecting rotor flowmeter?
- LM317 high power charger circuit
- A brief analysis of Embest's application and development of embedded medical devices
- Single-phase RC protection circuit
- stm32 PVD programmable voltage monitor
- Introduction and measurement of edge trigger and level trigger of 51 single chip microcomputer
- Improved design of Linux system software shell protection technology
- What to do if the ABB robot protection device stops
- Learn ARM development(19)
- Learn ARM development(14)
- Learn ARM development(15)
- Analysis of the application of several common contact parts in high-voltage connectors of new energy vehicles
- Wiring harness durability test and contact voltage drop test method
- From probes to power supplies, Tektronix is leading the way in comprehensive innovation in power electronics testing
- From probes to power supplies, Tektronix is leading the way in comprehensive innovation in power electronics testing
- Sn-doped CuO nanostructure-based ethanol gas sensor for real-time drunk driving detection in vehicles
- Design considerations for automotive battery wiring harness
- Do you know all the various motors commonly used in automotive electronics?
- EEWORLD University ---- Computer Control Technology
- You are invited to watch Tektronix Live Lecture Series - Power Supply!
- Please advise, why do you need to remove the motherboard before burning the flash?
- Antenna packaging issues
- DA output waveform test
- Common Problems in Using MSP430 Emulator
- 【GD32F103 video tutorial】GD32F103 video tutorial
- How is the unique ID of a microcontroller generated?
- An important representative enterprise in 70 domestic chip sub-sectors!
- Why 5G is crucial for IoT and high tech
京公网安备 11010802033920号