HVFO108 High-Voltage Fiber Optically Isolated Probe
18
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Connecting to the Test Circuit
WARNING
: The HVFO108 uses fiber-optic isolation to permit the transmitter to float above
ground without damaging the oscilloscope or harming the operator.
DO NOT touch the
transmitter or leads while connected to a live circuit.
These components are only rated 30
V
RMS
/60 V
DC
for hand-held use, and serious harm will result if you touch them while they
are floating above ground.
Connecting the Tips
For accurate measurements, connect all three inputs at the probe tip to the test circuit:
1.
Connect the blue Signal lead to the voltage that is to be measured, ensuring that the
attenuating tip used has sufficient input dynamic range to measure the signal (V
S
) but not
so much dynamic range that the measurement is noisier than desired.
2.
Connect the green Reference and black Shield leads to the floating board reference (V
CM
).
The example below left shows the tip lead sockets connected to a short stub on the
circuit board. 22AWG wires or 0.100” pitch pin headers work well with the tip socket.
Alternately, the micro-grippers may also be used to connect to the test circuit (right).
The micro-gripper has provisions for two connections, so the green Reference and black
Shield leads may be connected to one micro-gripper.
CAUTION:
The Reference and Shield wires are electrically connected inside the
tip. Failure to connect them to the same measurement potential will damage
the DUT and/or HVFO probe.
Properly connected tip when using stubs (left) or micro-grippers (right)
Positive voltages applied to the Signal input relative to the Reference and Shield inputs will
deflect the oscilloscope trace toward the top of the screen.
