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.
Hacker: I have controlled your computer. Xiaobai: How? Hacker: With a Trojan horse. Xiaobai: ... Where is it? I can't see it. Hacker: Open your task manager. Xiaobai: ... Where is the task manager? Ha...
: I use modusim to simulate the IP core dis_rom of Lattice. I don't understand why there are only two signals`timescale 1 ns / 1 ps `include "disrom.v" module disrom_tb; reg [5:0] Address; reg OutCloc...
[align=left][color=#000000]I downloaded the [font=Calibri]VxWorks[/font] image to the [font=Calibri]TigerSharc201[/font] motherboard through [font=Calibri]ftp[/font] and ran it. During the debugging p...
On the one hand, you can show off your hard work of 4 days and 3 nights; On the other hand, you can discuss your experience with XDJM who did the same question as you; On the other hand, you can let y...
I'm in urgent need of the integrated library of CD4000 series and 74CH series chips. As a newbie, when I draw in Altium designer 09 and import the PCB, it shows "Unknown pins". It seems that the pin d...
For example, there are two computers, called A and B. Machine B is connected to the network through machine A, which means that machine A can view any web page visited by machine B. But now I hope tha...
A single-chip microcomputer is also called a single-chip microcontroller. It is not a chip that completes a certain logical function, but a computer system integrated into one chip. In general, a c...[Details]
introduction
With the continuous optimization of surface mount technology (SMT) and the rapid development of chip component manufacturing technology, the application of chip mounters in the el...[Details]
1. Introduction
Automobile pollution is one of the most important issues that people are most concerned about and need to solve urgently. As an important method for detecting automobile exhau...[Details]
Due to the significant increase in electronic devices in automotive and industrial applications, the automotive and industrial markets continue to play an important role in China's electronics in...[Details]
Battery life is critical for portable applications. For applications such as smoke detectors, security devices, and thermostats, factory-installed batteries need to last for more than 10 years. The...[Details]
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]
Continuity test
A variety of devices need to be checked for continuity, including cable assemblies, printed circuit boards, and connectors to ensure that these components have the expected contin...[Details]
Only a small number of LED manufacturers can produce high-quality LEDs. For applications that are only used for simple indication, low-quality LEDs are sufficient. However, high-quality LEDs must...[Details]
1. Introduction
With the increasing popularity of fully automatic washing machines, consumers have higher and higher requirements for their environmenta...[Details]
Currently, each country is developing its own USB interface
charging specifications
, which leads to a major problem that a USB interface
charging
device manufactured in one country...[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]
0 Introduction
Ultrasonic waves
are mechanical waves with a frequency of more than 20KHz, and the propagation speed in the air is about 340 m/s (at 20°C). Ultrasonic waves can be gene...[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]
Currently, the commonly used solar cell technologies include monocrystalline silicon solar cells and polycrystalline silicon thin-film solar cells. Production process: Monocrystalline silicon solar...[Details]
Based on the actual situation, a remote intelligent anti-theft alarm device for home use, connected to the telephone line, simple to operate, and stable and reliable in operation is designed. When ...[Details]
Talking
京公网安备 11010802033920号
EEWORLD
