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.
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[color=#000][font=微软雅黑][size=21px] In order to provide you with a better experience when visiting EEWORLD, we will be upgrading and maintaining the system from 9:00am to 12:00pm (Saturday) on January ...
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1 Introduction
A wide variety of communication cables and control cables are widely used in various instruments and control equipment. Whether the cable is well-conducted and
whether
th...[Details]
System design is a complex process. It is not enough to just use ICs. There are many details to consider. This article uses a high-fidelity music playback system as an example to introduce how to s...[Details]
To differentiate their products in a crowded and competitive market, manufacturers of handheld devices often consider battery life and power management as key selling points for cell phones, PDAs, ...[Details]
July 11, 2012, Beijing - Altera Corporation (NASDAQ: ALTR) today announced the launch of 40-Gbps Ethernet (40GbE) and 100-Gbps Ethernet (100GbE) intellectual property (IP) core products. These core...[Details]
The data collector of the automatic weather station is generally designed based on a single-chip microcomputer or a PC/104 bus controller. It has the characteristics of good compatibility with PC, low...[Details]
MediaTek (2454) announced the acquisition of F-MStar (3697) and attracted the attention of IC design industry. This morning, Gartner Semiconductor Industry Research Director Hong Cenwei analyzed ...[Details]
With the rapid development of intelligent control technology, computers and information technology, the trend of information appliances IA (Information Application), computers and communications integ...[Details]
In the single-chip microcomputer system, in addition to display devices, sound devices are often used, and the most common sound device is the buzzer. Buzzers are generally used for some low-demand...[Details]
Experimental tasks
A DS18B20 is used to form a temperature measurement system. The temperature measurement accuracy reaches 0.1 degrees. The temperature range is between -20 degrees and +50 de...[Details]
In 2012, more than half of the cars in the European, Japanese and American car markets will be equipped with color displays, navigation systems, satellite communications and other in-vehicle infota...[Details]
At present, the traffic congestion in cities is quite serious. According to relevant news reports: In China, the traffic congestion has expanded from megacities such as Beijing, Shanghai, and Guangzho...[Details]
Introduction
X1226 has the functions of clock and calendar. The clock relies on hour, minute and second registers to track, and the calendar relies on date, week, month and year registers to tr...[Details]
In the "digital pressure measurement" experimental device of applied physics, the subject technical knowledge of analog circuits, digital circuits, sensors and single-chip microcomputers is used. In o...[Details]
The above is to use MB1404 as a stereo composite signal transmitter. You can use the internal high-frequency amplifier and oscillator or not! According to my experience, I still recommend beginners...[Details]
1 Embedded Systems
Embedded System refers to a collection of computer hardware and software with specific functions or purposes, which is divided into embedded software system and embe...[Details]
Embedded System
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