Owner's manual

1
INTRODUCTION
Chapter 1
INTRODUCTION
The Omega DB series of resistance decade boxes
is a family of instruments providing a very broad choice
of high-performance resistance sources. Any num-
ber of decades from one to eleven is available in a
choice of accuracies.
The Omega DB decade box is a precision resis-
tance source with excellent characteristics of stabil-
ity, temperature coefficient, power coefficient, and
frequency response.
The Omega DB Series employs very-low-resistance
switches with silver alloy contacts. A special design
keeps zero resistance to less than 1 mΩ per decade.
Self cleaning keeps the silver contacts from becom-
ing tarnished when unused, or when only low cur-
rents are passed through them. This is most often the
case when only minute test currents are drawn by
digital multimeters or other test instruments. Contact
resistance is stable and remains low and repeatable.
High-quality gold-plated tellurium-copper binding posts
serve to minimize the thermal emf effects which would
artificially reflect a change in dc resistance measure-
ments. All other conductors within the instrument, as
well as the solder employed, contain no metals or junc-
tions that could contribute to thermal emf problems.
The standard models offer a choice of one through
eleven decades. The panels are clearly labeled show-
ing the step size and maximum voltage and current
limitations for each decade.
With a resolution as low as 1 mΩ and a maximum
available resistance of over 111 MΩ, the Omega DB
series may be used for exacting precision measure-
ment applications requiring high accuracy, good sta-
bility, and low zero-resistance. They can be used as
components of dc and ac bridges, for calibration, as
transfer standards, and as RTD simulators.
The Omega DB Series may be rack-mounted to
serve as components in measurement and control sys-
tems.
Figure 1.1. DBX Series High Accuracy Decade Box