3
Channels
Go Direct Static Charge has two measurement channels:
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Charge—The default channel that is active when the sensor is connected is
Charge. This channel is calibrated in nanocoulombs and has a range of ±100
nanocoulombs.
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Potential—An alternative to measuring charge is measuring the difference of
potential between the red and black alligator clips. The sensor compares the
potential of the red clip to the assumed ground potential of the black clip.
Calibration
You do not need to calibrate Go Direct Static Charge. We have set the sensor to
match our stored calibration before shipping it.
Specifications
Range:
±100 nC (±10 V)
Maximum input:
±150 V
Typical bias input
current:
0.003 pA
Instrument time
constant:
0.1 s
USB specification:
USB 2.0 full speed
Wireless specification:
Bluetooth v4.2
Maximum wireless
range:
30 m (unobstructed)
Battery:
300 mAh Li-Poly Rechargeable
Battery life (single full
charge):
About 24 hours continuous data collection
Battery life (long term):
About 300 full charge cycles (several years,
depending on usage)
Care and Maintenance
Clean the sensor with a soft, damp cloth.
Battery Information
Go Direct Static Charge contains a small lithium-ion battery. The system is
designed to consume very little power and not put heavy demands on the
battery. Although the battery is warranted for one year, the expected battery life
should be several years. Replacement batteries are available from Vernier (order
code: GDX-BAT-300).
Experiment Ideas
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Use the sensor with a Faraday pail to investigate charging by induction.
Bring a charged object near the pail. What charge is measured? Ground the
pail and remove the charged object. What charge is measured?
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Use a Faraday pail to investigate charging by contact. Do this by dropping a
charged object into the can. All of the charge on the object will be
transferred to or induced in the can.
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Without a grounding strap, scuff your feet on carpet or pull off a sweater.
Hold your hand near a Faraday pail. Do you induce a charge? What sign?
Does a ground strap remove or reduce this effect?
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Charge various objects and determine the sign of the charge.
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Measure how quickly objects lose charge. Plot the charge as a function of
time; this will take some minutes on a dry day.
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Use Go Direct Static Charge and Faraday pail to observe the separation of
charge when two strips of invisible tape are pulled apart. On two 3-inch
pieces of tape, make a tab by folding over the top of each. Stick the
combination to the table top. Pull the combination off the table and run your
thumb or finger along the smooth side of the tape to neutralize the
combination. Then pull the top strip off the bottom strip. Individually insert
each strip into the Faraday pail to measure the charge. Simultaneously insert
them in the pail to measure the charge.
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Charge a Faraday pail by contact on the inside; add more charge. How much
charge can you add from the inside of the can? Can you add as much from
the outside? More? Less? Investigate.
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Use a second pail (not connected to the red lead as a detector) and charge it
by induction. Do this by charging an insulating object, holding it inside the
pail (inducing a charge on the outside of the can) and then briefly grounding
the pail. Remove the charged insulator and you’ve got a charged pail.
Measure the charge by testing it by induction or by touching it to the inside
of the detector pail.
Many of these tips are based on suggestions from Robert Morse, PhD.