Avtron Model T477W Bonding Meter
with B14703 Battery Pack Replacement Instructions
Part Number T477WC15292
Operating Instructions
Subject to the EAR, ECCN [9E610.a].
This information is subject to the export control laws of the United States, specifically including the Export Administration Regulations (EAR),
15 C.F.R. Part 730 et. seq. Transfer, retransfer, or disclosure of this data by any means to a non-U.S. person (individual or company), whether in the United States or abroad, without any
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2-2
C A U T I O N
Probes are equipped with sharp points. Exercise caution when handling probes to
prevent puncture wounds or scratches.
2.4
Minimizing Error Contributed by Probes
The above probe sets consist of two current leads which connect the Bonding Meter regulated current output to the unknown
resistance and two voltage sensing leads to measure the voltage developed across the unknown. The voltage sensed is small and
the current is alternating; therefore, a small transformer effect (coupling) exists between the current sourcing and voltage sensing
leads. This effect is best minimized when the voltage sensing leads are separate from the current leads and bound together for the
majority of the length of the cable as in the C15479 and C16695 probe sets. The distance that the voltage sense leads are spread
from each other is to be considered the cable loop diameter. The amount of meter reading error caused by the coupling effect on
metal surfaces is directly proportional to the cable loop diameter. Minimizing the cable loop diameter with any of the five probe
sets is advised to achieve the most accurate reading possible. See Figure 2-1.
2.5
C22161 Probe Set
This probe set utilizes two pistol grip style probes that facilitate obtaining a quick and easy reading. The best-rated meter
accuracy is obtained with the C22161 probe set, except in the 2 milliohm range. The accuracy in the 2 milliohm range is +
(1% of r 30 digits) and – (1% of r 10 digits).
NOTE
Each pistol grip probe is labeled “P” and “C” indicating which pin is for potential (voltage) and
current.
In the 2 milliohm range, reduce the cable loop diameter (see Figure 2-1) as much as possible to
minimize reading errors.
Figure 2-1.
Two Pistol Grip Probes with a Pair of Probe Tips
