1. Module 5: Digital Techniques and
Electronic Instrument Systems
5.12 Electrostatic Sensitive Devices

2. Electrostatic discharge
 ESD: Electrostatic Discharge.
 The sudden flow of electricity
between two objects.
 Caused by imbalance of
electrons between the 2 objects.
 A field created by tens of volts
between the 2 objects is enough
to damage a RAM module.
 Walking on a vinyl floor can
generate up to 12,000V of static
electricity.
 ESD abbreviation can also mean
“Electrostatic Sensitive Device”

3. Common Electrostatic Sensitive Devices &
actions causing ESD.
 Devices prone to ESD:
 MOSFETS
 CMOS ICs (Chips)
 Computer cards (CPU, GPU, etc.)
 LED, Diodes
 Actions causing ESD:
 Opening a plastic bag.
 Removing a tape from a roll or a container.
 Transporting computer components around with trays or
carts.
 Dry environments (non-humid) increase the possibility of
ESD.

4. ESD Prevention of working personnel
 Methods to remove
charge from the human
body:
 Touching metallic objects.
 Wrist band.
 Antistatic garment.

5. Other methods to prevent ESD when
working with electronic equipment
 Avoid touching connections or
pins.
 Ground all test equipment.
 Use Antistatic mat:
 Made a low resistance
material (10ΚΩ to 100ΜΩ) that
is grounded. It allows slow
discharging.
 Use Antistatic Agent:
 A compound used that makes
the surface of a material
conductive, thus reducing or
preventing ESD. Usually
absorbs moisture from the air.
 They are often added to jet
fuels.

6. ESD Preventing Materials
 Conductive Materials:
 Materials with resistance between 1ΚΩ & 1ΜΩ/m2
 Dissipative Materials:
 Materials with resistance between 1ΜΩ /m2 & 1ΤΩ /m2
 Shielding Materials:
 Materials that attenuate current and electric fields.

7. Static electricity on the aircraft
 The aircraft picks static charges from rain, cloud,
snow etc. (precipitation static)
• Strong charges developed between different parts of the plane
can break down the insulator between them.
• Problems caused by static electricity on the aircraft:
Material damage, Corrosion, Electromagnetic interference etc.

8. Corona Threshold and
Static electricity control
 The Corona Threshold: High velocity gasses exiting
the engine  Static electricity dissipates
surrounding atmosphere from sharp edges EMF.
 Solutions to control static electricity:
 Bonded (i.e. interconnection) of electronic equipment.
 Wickes (to eliminate static electricity dissipation from
sharp edges).

9. Wicks

10. ESD signs