Precision AC Current Shunt Set
Theory of Operation
19
Current Input
Connector - Inner
Current Input
Connector - Outer
Segment Top
Side Copper
Segment Bottom
Side Copper
Voltage Output
Connector - Inner
Bulk Foil Resistor
A
C
B
feh006.png
Figure 4. Current Shunt - Simplified Electrical Diagram
The PCB designated
A
in Figure 4 is copper clad on both sides. PCBs
B
and
C
are single
sided. Current flows into the shunt through the input connector, through one side of the
PCB
A
, along one side of the struts to the resistor. The current return is through the
resistor and along the other side of the struts and end PCB to the input connector. The
voltage across the resistor is carried by the strut to the dual PCB end (
B
and
C
in Figure
4) and to the output connector.
The parallel current paths provided by the PCB struts and ends minimize mutual
inductance. Using numerous bulk foil resistors reduces skin effect in the resistive element
and provides excellent stability.
Boxed Shunts
With the exception of the 1 mA Current Shunt the boxed Current Shunts are electrically
simpler than the coaxial versions. Inductance and self heating become less of a problem
so the resistive elements can be enclosed to reduce external influences. The 1 mA Current
Shunt includes a battery powered amplifier to buffer the shunt resistance from loading
effects.
Summary of Contents for A40B
Page 6: ...A40B Instruction Manual iv...
Page 8: ...A40B Instruction Manual vi...
