& ESD DISCHARGE SIMULATOR
& it's ESD Discharge Simulator, have been designed as a quick
check indicator to quantify the maximum voltage seen inside
a metallized shielding bag. ESD Discharge Simulator (1000D)
delivers, a (HBM) Human body model charge of 1000 volts. Shield-Check
(SC-0-300) records the peak voltage seen inside the bag, via
a row of LED's sensing 10-20-30-40-50-100-200- 300 volts.
The maximum voltage sensed will remain visible until the operator
presses the reset switch.
portable mains powdered ESD Discharge simulator and
near credit card size Shield-Check sensor, can be used
for a quick evaluation of new and used shielding bags.
Complete with Stainless steel Discharge probe, Reference
plate, and test leads.
SC-0-300 POWER: 3 x 3 volt lithium coin cell batteries
1000D POWER: mains 120/240Ac
SC-0-300 SIZE: 106mm x 60mm x 21mm
1000D SIZE: 150mm x 115mm x 57mm
and Answers about Shield-Check
Why use a (HBM) Human Body Model of 1000 volts?
Other Voltages may be used at the operators discretion, however
users should be sensitive to the voltage breakdown limitations
of the material under test as well as the various components
used in the Shield- Check sensor.
is the sensor unit near credit card size?
This allows the user to measure the performance of almost
any size of metallized shielding bag.
should the user not touch the probe, bag under test or reference
plate, whilst delivering 1000v (HBM) from the discharge simulator?
The sensor detects the differential voltage between top and
bottom sensing discs through the shielding bag. If the users
touches the probe, bag, or reference plate, the 1000v (HBM)
will reference to the user rather than reference plate.
if no voltage LED's light after the 1000v discharge has been
This is due to the effective shielding of the bag under test
I.E. less than 10 volts has been sensed.
the 10 volt LED lights what voltage has been sensed?
10 volts or greater than 10 volts but less than 20 volts.
The same principal applies for 20 volts 30 volts etc.,
a good quality large shielding bag show a lower voltage reading
than a good quality small shielding bag?
Yes because the metallized layer will absorb the 1000v, over
a larger surface area.
the sensor detect pin holes in the surface of a shielding
No! because the 1000 volt (HBM) is absorbed by the metal layer
of the shielding bag. A shielding bag is an electrical Faraday
cage, not a water tight container. A clean cut through a shielding
bag when laid flat might not be detected by the sensor. The
users visual inspection should identify cuts and holes.
I cut a big hole out of the back of the bag will the sensor
Only if the top and bottom sensing discs on Shield-Check are
making direct contact with the bag material under test.
I deliver 1000v (HBM) from the discharge simulator, if the
bag is good (less than 10 volts) and shows no voltage reading
on the sensor, even through the power LED is on. How do I
know than I have carried out a test on that shielding bag.
Less obvious is that the 1000v relay inside the simulator
will click, or the bag may move slightly when the change is
applied. But to verify both simulator and sensor, remove the
sensor from the bag place it on the reference plate and put
the discharge probe on the sensors top disc. Then discharge
directly, your reading will be in excess of 300 volts.
if two or more voltage LED's light at the same time?
A spilt signal or (Ringing) has occurred through the bag under
test. The sensor receives two or more peak voltage signals
at the same time indicating poor shielding.
Charge remains between the probe and reference plate after
the user has taken the previous reading?
When not delivering a pulse, a 10 meg Ohm resistor between
the probe and reference plate ensures no residual charge remains.
if I cut the heat sealed edges off one or both sides of the
The sensor has been designed to check the shielding ability
of the bag in it's formed state. Not the ability of the metallized
film used to produce the bag. By cutting off the sealed edges
you no longer have a bag to measure just the material.
makes a metallized shielding bag bad?
The nose edge of the bag excessively creased or damaged, the
sealed edges of the bag inconsistent, the metallized layer
too thin, folds in the bag or snowball effect where the bag
has been creased all over.
is the voltage sensed nearly always the same if the bag end
is open or closed?
The capacitance of the air gap at the open end of the bag
is greater than the resistance of the metallized layer around
the bag. The 1000 volts will always find the quickest path
to Ground/Earth. (In our case the reference plate)
DESCRIPTION OF SHIELD-CHECK SYSTEM
Shieldcheck provides a quick and convenient check, on the
effectiveness of a metallized shielding bags capability to
protect its contents against Electro-static Discharge (ESD).
A compact sender provides a 1000volt human body model (HBM)
discharge which is received by a battery operated sensor unit
placed inside the bag. The choice of 1000volt for the test
pluse is to avoid break down of the material under test. A
bounce free leading edge is achieved by use of a mercury wetted
The sensor unit detects a voltage pulse between its two sensor
plates, and remembers the level which has been exceeded displaying
it by means of the eight LED display. The nominal levels of
detection are as follows.
High speed integrated circuits ensure that fast pulses are
registered. DC coupling permits easy checking of the threshold
Shieldcheck and its discharge simulator are based on the EIA541
capacitive probe method. When not delivering a pulse, a 10meg
Ohm resistor between the probe and earth reference plate ensures
no residual charge remains from previous use. Amongst other
Shielding is a function of the resistance around the bag so
the pulse amplitude will be dependent on where in the bag
the Shieldcheck sensor is placed. When a pulse is delivered,
one of the LEDs will light unless the sensor detects less
than 10 volts between its plates. This indicates that the
peak exceeds the indication but not the next higher value.
Thus when the 20volt LED lights, the peak was between 20 and
Switch on Shield-Check via the right angle switch below part
Make sure the POWER ON LED is visible.
Insert Shield-Check into shielding bag.
When (HBM) Human Body Model pulse has occurred from 1000D
Discharge unit the maximum voltage sensed will remain until
the operator has pressed the reset switch. (Using a pen or
If NO LED has been illuminated this is due to the effective
shielding of the bag i.e. 0-9 volts sensed. If a voltage greater
than 10 volts has been sensed, one of the eight LEDs will
light until reset.
To change batteries unscrew the 4 self tapping screw in the
rear of the case. Remove all three batteries CR2032 type,
and replace. The + positive of the battery should make contact
with the battery clip. The-negative of the battery should
make contact with the PCB. Make sure that when not in use
the unit is switch OFF.
DISCHARGE SIMULATOR 1000D
Connect appropriate country plug to mains lead. Make sure
that the voltage select switch is in the correct position
i.e. 120v/240v. The unit has a 100ma fuse located in the rear,
to protect against electrical damage. Plug in to mains socket
and switch on.
Switch on neon front panel power switch. (Marked ON/OFF)
Connect black test lead in to GND socket, and red test lead
into 1000 volts socket using 4mm banana plug ends. Attach
stainless steel reference plant to the other end of the black
test lead, and attach the small circular probe 30mm high 25mm
diameter, to the other end of the Red test lead.
When Shield-Check is in position, make sure that the material
under test and Shield-Check are making contact with the reference
plate. Place the circular probe on the surface of the bag
over Shield-Check sensor plate.
Press the Black discharge button to deliver 1000 Volts (HBM).
Make sure that the operator does not touch the bag under test,
the reference plate or stainless steel probe