Computers, RAM, and Static Precautions

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Having bought RAM on eBay I am surprised at the lack of anti-static precautions taken by sellers. Without naming names I wish to comment that, as with CPUs especially, and indeed with most if not all CMOS computer circuitry, anti-static precautions are a nescessity at all times when handling, packing, and storing any item of computer equipment or componentry. This is even more important than avoiding exposure to damp and high temperatures, as damp can always be dried out before fitting/use, and most modern circuitry can withstand temperatures above 60 degrees centigrade. :

The Technical Bit.

Computer components such as RAM sticks, processors, motherboards, graphics cards...you name it, either consist of a combination of discrete transistors and integrated circuits, or "chips", containing in some cases millions of transistors, - or are themselves chips, as in the case of a CPU or processor. These transistors are in most cases - other than some types of power-controller transistors - of the MOSFET variety.
In very basic terms, the guts of these individual transistors consist of a microscopic layer of doped semiconductor material, laid on and adhered to a microthin silicon wafer, with a tiny electrostaically-effective gate which is insulated from the semiconductor material by an incredibly-thin and fragile insulating material alongside the semiconductor. Under normal circumstances and in normal operation the gate, being totally electrically insulated from the semiconductor material, electrostatically regulates the flow of electrons through the semiconductor material between the drain and the source connections at either end of the semiconductor, depending upon its' electrical potential - which is how the transistor works.
Due to the fragile nature of the insulating layer between gate and semiconductor, however, it doesn't take much in terms of overload to break down the insulation between the gate and the semiconductor, creating a low-current potential divider with the gate as the centre connection, i.e connected to the semiconductor through the break in the insulation, and thus ruining the action and function of that individual transistor. This basically ruins the individual transistor.

Static electricity can build up on virtually any and every surface, even the human body in some cases, to a potential of thousands, sometimes millions of volts, and at currents greater than the insulated gate of a MOSFET is capable of withstanding. When these charges are applied to any type of MOSFET circuitry, usually without even realising that the electrical charges are present, then the obvious occurs. - The transistor(s) break down as a result, due to the insulating layer depleting under overload, and suddenly the device is rendered inoperative, AKA ruined, broken, kaput, finito, had it, shagged, destroyed, fried...

You may think that with millions of transistors it wouldn't hurt if one or two don't work; after all people don't die if a few cells in their body die, or they injure themselves slightly. The human body and the electronic circuit are totally different in many respects; and this is one of them. : The human body can replace dead cells in days, and can bypass the function of dead cells until new ones are grown by its automatic-repair process, at least to a certain extent. Within an electronic circuit, however, if a transistor dies then the function in the pathway of a particular electron flow is rendered inoperative and the device can and usually does malfunction as a result. In many cases this triggers a chain-reaction in which many other transistors along or connected to that path also die; and when a transistor is dead it's dead forever: no afterlife or reincarnation. -This destruction can sometimes happen naturally with the age of the component causing it to break down with usage; but it's relatively rare in modern electronics. A static charge, however, can "fry" a device; literally causing a micro-detonation of the active components of many transistors on a microscopic level within the device, rendering it useless.

How to Avoid Damage

So bearing the above in mind; what needs to be done to prevent this happening? Anti-static precautions should be adhered to at all times rigorously when handling CMOS and MOSFET circuitry; which encompasses nearly all the circuitry within a computer, except for some parts of the PSU or Power Supply Unit which have a lot of discrete components and incorporate mainly bipolar and other types of transistor, as well as voltage regulators etc.
Anti static precautions are aimed at preventing static electrical charges from reaching a device; and accomplishing that end is not quite as simple as it sounds. People seem to think that since polythene is a good electrical insulator, if they wrap RAM etc in polythene then it'll prevent it from being exposed to charge. WRONG. Polythene is one of static electricity's favourite places to lurk. A static charge builds up easily on any polythene surface by means of friction with another material or sometimes even friction with itself. Nylon is also an excellent static-capacitor, as is your carpet, your leather sofa, your dress or shirt, woolen jumper or cardigan, hair...
So what if I pack electronics naked? Your naked body is a conductor of static electricity, from the carpet, your sofa, your dress... - 'Straight into the nearest transistor; and you needn't nescessarily feel a shock either when it happens. (If you do then at least you can be 99.9% certain that the device is ruined without testing it.).
To avoid damaging circuitry you need to keep all possibility of static discharge well away from it.

Ground Thyself

An anti-static wristband should be worn at all times when handling semiconductors or semiconductor-based , CMOS, MOSFET, whatever, circuitry. : Go into any electronics lab, even at college, and you'll see everyone wearing one on their wrist. This is providing any static charge that comes into contact with their body with a path to electrical earth; the quickest path to destination, which is the path all electricity will take in all cases.

All handling of electronic circuitry and components should be within a static-proof environment. (I once saw an eBay advertisment for a motherboard with a picture of the motherboard laid on the carpet. As soon as that board is touched static electricity will travel from the carpet, through the board and its components, through the hand of the handler - wherther or not they're wearing an anti-static wristband, and on its way to the easiest path to earth.) If a static electrical charge contacts the component just once then it's fried, dead, useless. Always always always pack electronics in an anti-static bag. NEVER pack them in polystyrene or polythene. - You will ruin them and your buyer will ask for a refund. Always wear an anti-static wristband when touching a circuit-board or "card"; preferrably on the wrist attached to the hand with which you are holding it. NEVER allow the component to come into contact with the carpet, (Avoid carpets in the packing/handling environment if at all possible.) a polythene, polycarbonate, polystyrene, poly methyl methacrylate, poly-whatever surface, also metal, plants, and don't allow it into a strong electromagnetic or electrostatic field. (Microwave, transformer, close to a television screen, etc.) Also avoid touching any exposed metal part or component on the board/card if at all possible. (Other than the backing plate of a graphics card... but even in that case ensure that you are earthed.)

I've recieved RAM wrapped in bubble-wrap before now. - 'Not a good idea. : Take care of your electronic parts, sellers - otherwise you'll only be asked for refunds and lose money, as the components won't work when your buyer receives them.

 

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