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.
I am currently working on UCOSIII and have encountered a problem with CAN bus reception. I hope you can help me and give me some advice! The specific phenomenon is that when 4 different messages are s...
[i=s]This post was last edited by SHU_2017 on 2018-12-5 08:49[/i] Background: I designed a vehicle controller to control the movement of three motors. I have encountered the problem of insufficient po...
As digital isolators become more prevalent in industrial and automotive applications, designers are faced with a plethora of available options. How do they choose the right device for their system? Fa...
I just came into contact with 32-bit microcontrollers. The company I was interning at used Renesas microcontrollers. According to the promotional materials, Renesas is now the company that produces th...
Hello everyone, for the initial study of SAE1939 protocol, thank you for your help. Please forgive me for any mistakes in the expression. For example, the figure above {:1_138:} is obtained from the q...
From the PIC16F946 datasheet, we know that there are two ways to write values to the LCD for display:
1. Directly write the value to LCDDATA1~LCDDATA23
2. Use disconnect t...[Details]
With the advocacy and implementation of the government's Safe City Plan, the security market has increasingly higher requirements for the clarity of surveillance images. Imagine that after a case o...[Details]
At very low temperatures, certain metals and alloys lose their resistance to electric
current
and become
superconductors
. Two parameters that are often measured are the transition ...[Details]
Introduction
Nowadays, people pay more and more attention to the security alarm system, and people have higher and higher requirements for the functions and performance of the alarm. This paper prop...[Details]
With the rapid development of wireless
digital communication
, more challenges have been raised for integrated circuit design and testing. In the product design stage, in order to ensure
t...[Details]
The launch of Shenzhou IX is imminent, and Tiangong is welcoming visitors again. Yesterday, Professor Fu Qiang, Vice President of the Institute of Science and Industrial Technology of Harbin Instit...[Details]
Power supply is often the most easily overlooked link in the circuit design process. In fact, as an excellent design, power supply design should be very important, which greatly affects the perfor...[Details]
The overall operating performance of an electric car depends first on its battery system and motor drive system. The drive system of an electric car is generally composed of three main parts: a con...[Details]
DigRF
is
poised to replace the two main forms of data communication paths between RF and baseband semiconductor devices:
analog
signaling, and proprietary digital signaling (paralle...[Details]
Various electronic and electromagnetic interference inside and outside the car often puts automotive electronic equipment in dangerous working conditions, degrading the performance of electronic eq...[Details]
Today, as information becomes an increasingly important resource, strong market demand and the development of microelectronics technology have led to the rapid development of portable electronic sy...[Details]
Improving the coordination of material handling and internal transportation between departments in modern factories is an important measure to achieve full automation of production. Traditional mat...[Details]
In the industrial production process, flow measurement is a widely used measurement physical quantity. In special cases, such as vertical oil wells, when it is not easy to install probes outside the p...[Details]
Real-time operating system RTOS
京公网安备 11010802033920号
EEWORLD
