Electronic – Can BJT transistors be damaged by static electricity

Antistatic Bags & Conductive Bags

These plastic bags normally have a distinctive color according to its properties:

• Silver for metalized PET film and other similar plastics
• Pink or black for polyethylene

(*) The polyethylene model can also be made as foam or bubble wrap, either as sheets or bags.

To create the anti-static effect, the black bags or silver bags are slightly conductive, forming what is known as a Faraday Cage around the item to be protected avoiding any discharges from being deposited onto the protected devices as the bags are handled.

“METALIZED SHIELDING” BAGS (Silver in color).

• DO NOT CREASE the bag, as this can breakdown the integrity of the metalized shield!
• You should not use any bags damaged with TEARS AND / OR PUNCTURES, as these can DESTROY THE FUNCTION OF THE FARADAY CAGE!
• Metalized Shielding bags CAN DETERIORATE with use, MONITORING them for effectiveness is VERY IMPORTANT!

ESD Bags: To Shield Or Not To Shield

Antistatic Bags

Antistatic bags are typically coated with a topical antistatic agent that helps minimize the generation of a static imbalance ... Some antistatic bags are made with an antistat built into the films layers and tend to be more reliable and cleaner then the topically treated ones. A good bag has antistatic properties on both the inside and outside of the bag’s film construction.

Dissipative Bags

Bags with the films surface resistance in the dissipative range are preferred because charge dissipates across the surface at a controlled rate. Most dissipative bags also have the property of being antistatic. These are good general bags to be used in non-critical environments.

Metalized Shielding Bags

Metalized shielding bags have either a metal film embedded into the bag film construction or coated onto an existing layer. This metal film acts as an electrical shield against electrical discharges from the outside of the bag. Depending on the energy and duration of the discharge and the thickness of the metal film, an ESD event is typically spread out over the outer surface of the metal film and if fully enclosed, i.e. the bag is sealed, then the charges current from the ESD event is contained to the outside (outer surface) of the metal film, i.e., providing a region of no electrostatic fields within the bag, thereby protecting the contents within. This effect is known as the Faraday Cage Effect and is commonly used in controlling ESD via metalized shielding bags, conductive bags and the conductive tote box with a cover.

These bags are pink for identification purposes. These bags prevent static build up, but do not protect their contents much from external sources of static. There are also silver bags that protect from those external sources and blue bags that are almost the same as the pink ones but work at a greater humidity range.