Glossary of Terms

Balanced Load
AC power system using more than two wires, where the current and voltage are of equal value in each energized conductor.

Balco
A nickel-iron alloy generally used for low cost resistance sensors. Temperature coefficient is (4800 ± 200) ppm.

Bandwidth
The range of frequencies over which an instrument provides accurate measurement.

Bias Current
Current that flows out of an amplifier's input terminals, which will produce a voltage drop across the source impedance - in a perfect amplifier this error term would be zero.

Bifilar
A noninductive winding, i.e.; 2 parallel strands of wire joined at one end with the two leads coming out of the other end.

Bipolar
The ability of a panel meter to display both positive and negative readings.

Boiling Point
(of water) 212°F, 100°C, 373.2°K at one atmosphere pressure.

Bourdon Tube
Used in pressure recorders; an oval metal tube bent into a C-shaped arc with one closed end. When pressure is applied to the open end the tube tends to straighten which moves the closed end. The pointer is attached to this end.

BTU
(British Thermal Unit) The heat required to raise the temperature of one pound of water 1°, or 1/180 the heat required to raise one pound of water from 32 to 212°F at one atmosphere pressure.

Burden
The electrical load taken from a circuit by measuring instruments expressed in volt-amps (VA) or watts. In potential or current transformers, burden in VA is the maximum load the transformer can support while operating within its accuracy rating.