Teledyne t320u Manuale Utente

Teledyne API – Model T300/T300M CO Analyzer 

A Primer on Electro-Static Discharge 

Potentially damaging electro-static discharges can occur:  

  Any time a charged surface (including the human body) discharges to a device.  

Even simple contact of a finger to the leads of a sensitive device or assembly can 
allow enough discharge to cause damage.  A similar discharge can occur from a 
charged conductive object, such as a metallic tool or fixture.   

  When static charges accumulated on a sensitive device discharges from the device 

to another surface such as packaging materials, work surfaces, machine surfaces or 
other device.  In some cases, charged device discharges can be the most 
destructive.   

  A typical example of this is the simple act of installing an electronic assembly into 

the connector or wiring harness of the equipment in which it is to function.  If the 
assembly is carrying a static charge, as it is connected to ground a discharge will 
occur. 

  Whenever a sensitive device is moved into the field of an existing electro-static field, 

a charge may be induced on the device in effect discharging the field onto the 
device.  If the device is then momentarily grounded while within the electrostatic field 
or removed from the region of the electrostatic field and grounded somewhere else, 
a second discharge will occur as the charge is transferred from the device to 
ground.   

  I didn’t feel a shock so there was no electro-static discharge:  The human 

nervous system isn’t able to feel a static discharge of less than 3500 volts.  Most 
devices are damaged by discharge levels much lower than that. 

  I didn’t touch it so there was no electro-static discharge:  Electro Static charges 

are fields whose lines of force can extend several inches or sometimes even feet 
away from the surface bearing the charge. 

  It still works so there was no damage:  Sometimes the damaged caused by 

electro-static discharge can completely sever a circuit trace causing the device to 
fail immediately.  More likely, the trace will be only partially occluded by the damage 
causing degraded performance of the device or worse, weakening the trace.  This 
weakened circuit may seem to function fine for a short time, but even the very low 
voltage and current levels of the device’s normal operating levels will eat away at 
the defect over time causing the device to fail well before its designed lifetime is 
reached.   

  These latent failures are often the most costly since the failure of the equipment in 

which the damaged device is installed causes down time, lost data, lost productivity, 
as well as possible failure and damage to other pieces of equipment or property. 

  Static Charges can’t build up on a conductive surface:  There are two errors in this 

statement.   

  Conductive devices can build static charges if they are not grounded.  The charge 

will be equalized across the entire device, but without access to earth ground, they 
are still trapped and can still build to high enough levels to cause damage when they 
are discharged. 

  A charge can be induced onto the conductive surface and/or discharge triggered in 

the presence of a charged field such as a large static charge clinging to the surface 
of a nylon jacket of someone walking up to a workbench. 

  As long as my analyzer is properly installed, it is safe from damage caused by 

static discharges:  It is true that when properly installed the chassis ground of your 
analyzer is tied to earth ground and its electronic components are prevented from 
building static electric charges themselves.  This does not prevent discharges from 

06864B DCN6314