The properly and electrostatically measured taping materials are used for the components, but attention should be paid to the fact that there is some danger the parts absorb on the top
tapes to cause a failure in the mounting and the parts are destructed by static electricity (more than 1kV : 1J, 2A, 2B, 2E 0.5kV : 1E, Human Body Model 100pF 1.5kΩ) to change the
resistance in the conditions of an excessive dryness or after the parts are given vibration for a long time as they are packaged on the tapes. Similarly, care should be given not to apply the
excessive static electricity when mounting on the boards.
●
Ionic impurities such as flux etc. that are attached to these products or those mounted onto a PCB, negatively affect their moisture resistance, corrosion resistance, etc. The flux may
contain ionic substances like chlorine, acid, etc. while perspiration and saliva include ionic impurities like sodium (Na
＋
), chrorine (Cl
−
) etc. Therefore these kinds of ionic substances may
induce electrical corrosion when they invade into the products. Either thorough washing or using RMA solder and flux are necessary since lead free solder contains ionic substances.
Washing process is needed, before putting on moisture proof material in order to prevent electrical corrosion.
●
Please pay attention that the top of an iron does not direct touch to the components. There is a risk that may cause a change in resistance. Take care that another risk may happen that
the protecting coat is carbonized in an instant when touched directly by the top of the iron, also climatic-proof for electric corrosion or insulation of protecting coat may be dropped down.
Be sure not to give high temperature on the top of the iron as it will degrade the protecting coat.
●
Avoid storing components under direct sun rays, high temperature/humidity. Direct sun rays will cause quality change of taping and difficulty of keeping appropriate peeling strength. 5∼
35℃/35∼75%RH, there is no deterioration of solderability for 12 months, but take special care for storing, because condensation, dust, and toxic gas like hydrogen sulfide, sulfurous acid
gas, hydrogen chloride, etc. may drop solderability.
[color=#454545][font="]RAM for Algorithm: Specifies the RAM area used for burning programs, usually a section of on-chip space on a microcontroller. [/font][/color][size=14px][color=#454545][font="][s...
[color=#000000][font=微软雅黑][size=3]Toshiba[/size][/font][/color][color=#000000][font=微软雅黑][size=3]The stepper motor driver introduction course is now online. The explanation is meticulous and rigorous,...
[size=3][color=#000][font=微软雅黑]Multi-PK grouping, user scenarios and general scheduled task interfaces have been released. [/font] [/color][color=#000][font=微软雅黑]The above OPEN API users/manufacturers...
[size=10px] I customized a Wince system based on simulation under PB5.0. After sysgen, there are no errors and warnings. I want to download the image to the virtual machine, but the following error oc...
As the title says, we are now collecting topics suitable for undergraduate graduation projects. I am working on battery management. This year, I hope to make a battery pack insulation internal resista...
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In our common sense, the word technology often has two definitions. The first is the technology sealed in the laboratory. They are like flowers on the mountain top. Only a few people on the mountai...[Details]
China Energy Storage Network News:
On April 24, State Grid Corporation of China (hereinafter referred to as "SGCC") and China Southern Power Grid Co., Ltd. (hereinafter referred to as "CSGC")...[Details]
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Development Background: 1. Main chip - STM32F207VCT6; 2. TCP/IP protocol stack - LWIP, transplanted based on ST routines; 3. Operating system - none (bare metal); Anomalies: 1. Power on the device wi...[Details]
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This is also a routine in the development board, with explanations of the key points. The program is as follows: /********************************************************* Program notes: First...[Details]
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in the mobile phone industry
, Xiaomi's own processor Pengpai S1, AI
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1. Function and purpose There are two pins BOOT0 and BOOT1 on each STM32 chip. The level status of these two pins when the chip is reset determines which area the program starts from after th...[Details]
OSC_IN and OSC_OUT are external crystal pins by default. If you do not use an external crystal oscillator on the STM32, how to connect OSC_IN and OSC_OUT If you use the internal RC oscillator instead...[Details]
The first one is a DMA mode of multiple channel acquisition void ADC_DMA_Config(void) { ADC_InitTypeDef ADC_InitStructure; RCC_HSICmd(ENABLE); while (RCC_GetFlagStatus(RCC_FLAG_HSIRDY) == RESET); ...[Details]
This example sets up a button to adjust the square wave of different frequencies (multiples of 100) from 100-1000hz. In addition, serial port communication is added, and the corresponding frequency c...[Details]
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