From the color of the circuit board, see if the manufacturer has jerry-built materials.

There is gold and copper in the circuit boards of mobile phones and computers. Therefore, the recycling price of waste circuit boards can reach more than 30 yuan per kilogram. It is much more expensive than selling waste paper, glass bottles and iron.

From the outside, there are three main colors on the outside of the circuit board: gold, silver and light red. Gold is the most expensive, silver is the cheaper, and light red is the cheapest.

From the color, it can be seen that hardware manufacturers do not jerry, in addition, the circuit inside the circuit board is mainly pure copper, if exposed to air, it is easy to be oxidized, the outer layer must have the above protective layer. Some people say that golden is copper, which is not right.

Golden



The most expensive gold is real gold. Although only a thin layer, but also accounting for nearly 10% of the cost of circuit boards. Some places along the coast of Guangdong and Fujian specialize in purchasing waste circuit boards and stripping off gold, making considerable profits.

Gold is used for two purposes, one is to facilitate welding, the other is to prevent corrosion.

The gold finger of the memory bar eight years ago is still shining. If copper, aluminium and iron were replaced, the rust would not be used.

Gold plating layer is widely used in welding pad, golden finger, connector shrapnel and other parts of circuit board.

If you find that some circuit boards are all silver, it must be jerry-building. The industry term is "costdown".

Mobile phone motherboards are mostly gold-plated, computer motherboards, audio and small digital circuit boards are generally not gold-plated.







silvery

Golden is gold, silvery is silver?

Of course not. It's tin.

Silvery boards are called tin spraying boards. Spraying tin on the outer layer of the copper circuit can also help to weld. But it can't provide long-term contact reliability like gold.

Tin spraying board has no effect on the components that have been welded, but for the pads exposed to air for a long time, the reliability is not enough, such as grounding pads, pin sockets, etc. Long-term use is easy to oxidize and rust, resulting in poor contact.

The circuit board of small digital products, without exception, is tinplate. There's only one reason: cheap.

Small digital products like tinplate very much.

Light red

OSP, organic soldering film. Because it's organic, not metal, it's cheaper than tin spraying.

The only function of this organic film is to ensure that the inner copper foil is not oxidized before welding. The film evaporates as soon as it is heated during welding. Soldering tin can weld copper wires and components together.

But very corrosion-resistant, an OSP circuit board, exposed to air for more than ten days, can not weld components.

Many computer motherboards adopt OSP technology. Because the circuit board area is too large to use gold plating.


Circuit Board of OSP Technology, The colour is light red.