What is the Symbol for the Black Electronic Component?

[weitao]

What is this ( the black colour one )?

 

[vk6kro]

That is an integrated circuit. They are made like this in cheap, mass produced equipment.
I have seen one in a digital thermometer.

They look like a blob of plastic, but they are fairly immune to vibration and moisture. However if they failed, the whole printed circuit board would have to be discarded.

 

[berkeman]

What is this ( the black colour one )?

Just to add a little bit to vk6kro's post -- it's called "chip on board", or COB. It's a technique for assembling an IC die onto a PCB, without first injection molding the die into a plastic package with leads, and soldering that onto the PCB. As vk6kro says, it is used in high-volume manufacturing of inexpensive devices, generally, and does not offer any rework capability.

 

[weitao]

this one ! What is this ?

 

[vk6kro]

Yes, that one. It is an integrated circuit.

 

[berkeman]

More info on COB:

http://www.siliconfareast.com/cob.htm

Once the die is wire bonded to pads on the PCB, it is covered by that black plastic blob to passivate it.

 

[weitao]

wat is the symbol?