ESD electro discharge precautions

 static current (ESD electro discharges) produce most commonly causes of moving people, low humidity, improper grounding, unshield cables, poor connections and moving machines .example walking across vinyl floor  may produce up-to 12 kv voltage .computer peripherals like mother board, hard drive and ram contain assembles with sensitive components it may damage due to static electricity. that why we have use anti static envelope cover to protect devices.

mother board and other electronic devices contains transistor, ic, micro  processors chips , CMOS logic and resistors devices can easy  damage 380 v  to  7 kv voltage electro static current ESD.

The smallest static voltage most people can feel is about 3500 volts. It takes less than one tenth of that (about 300 volts) to destroy or severely damage static sensitive circuits. Often, static damage is not sufficient to cause an immediate malfunction. Instead, it lurks in the background; a time bomb waiting for an opportunity to cause a system breakdown at some critical moment. A few simple precautions can significantly reduce the risk of system failure or malfunction due to static damage.

•   Treat all assemblies, components, and Interface connections as static- sensitive. Extra care pays big dividends.

•   When you unpack memory cards, Interfaces, and other accessories that are packaged separately from the computer, keep the accessories in their conductive plastic bags until you are ready to install them.

•   Before you install accessories in the computer or install optional assemblies into a peripheral, select a work area where potential static sources are minimized. Avoid working in carpeted areas, and keep body movement to a minimum while installing accessories. If possible, use a controlled-static workstation that Includes personnel grounding provisions (a typical workstation is shown later) to protect against static build-up.

If a controlled-static workstation is not available, follow these precautions.

•  Always handle accessories by their metal cover plates or by the plastic extractors located at two corners on each card. Avoid touching any of the metal circuitry on the card. When you are ready to configure an accessory, remove it from its protective bag and lay it on top of the bag while keeping your free hand in contact with the bag. Keep one hand in contact with the bag while you configure the accessory with the other. This technique maintains your body and the accessory at the same static voltage, thus preventing you from destroying a compo­nent due to static discharge.

•  When you install the accessory, keep one hand in contact with the plastic bag as you pick up the part with your other hand. For extra safety, avoid touching any metal circuitry on the accessory card (pick the card up by the plastic extractors on the rear corners of the card or by the metal cover plate that Is attached to interfaces). While you are still holding the accessory in your hand, move your free hand to an exposed metal surface on the back of the computer to drain any accumulated static from your body to the computer. Keep your hand in contact with the computer while you slide the accessory into the computer with your other hand.

•  For full static protection, be sure all covers are installed on the compu­ter before you connect it to the system.

•  Before you install Interface cables, be sure all power cords are con­nected to the computer and all peripheral devices. Verify that they are plugged into correctly wired power receptacles that provide a safety ground to the third conductor on the power cord. This provides an electrical ground path for static accumulations that could otherwise damage components that connect to the interface cable(s).

•  When connecting Interface cables, hold the cable connector In one hand, then place your other hand on a grounded surface on the computer or peripheral frame. This ensures that you have discharged any accumulated static from your body to the electrical system ground through the device frame.

You can now safely plug the Interface cables in to their mating inter­face and peripheral rear-panel connectors. When the cables are con­nected, engage the connector retainers so that the connectors cannot come loose and cause a system malfunction or component failure.

• Keep the conductive plastic bags shipped with accessories. If it becom­es necessary to remove an accessory for service or storage, put the accessory back in an antistatic bag for continued protection.