Chapter 3
Hardware Overview
3-8
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The NI PXI-8250 has self-resetting fuses rated at 1 A/125 V on the front
end and one-blow fuses rated at 4 A/125 V on the back end of the card to
protect the card from excessive current draw. Refer to Figure 3-1 for the
locations of these fuses.
When current is exceeded on any of the rails (the current limits are provided
in Table 3-2), the self-resetting fuses will open the circuit. These fuses are
designed to reset themselves and do not need to be repaired.
As a fail-safe, one blow fuses have also been added to ensure that excessive
current is stopped if a self-resetting fuse fails to operate properly. In the
event that any of the one-blow fuses blow, the board must be returned for
repair.
Table 3-2.
Fused Power Output Ratings
Voltage Rail
Maximum Allowed Current Draw
+5.0 V
0.75 A
+3.3 V
0.75 A
+12.0 V
0.25 A
–12.0 V
0.25 A
