Glossary of Terms - O
O.D. (Tubing VS. Pipe)
Outside diameter, the proper way to size T/C or RTD sheath tubing vs. inside diameter used for pipe sizing.
The difference between two bias currents drawn by the inputs of a differential input stage of an electronic meter.
The deviation from zero output voltage of an amplifier having zero input voltage.
Oxygen free high conductivity copper, one leg in type T thermocouples, the other leg being an alloy of approximately 60/40 copper nickel.
Relates to total terminal resistance of voltmeters. For example, a meter with 1000 ohms/V, and 300 volts full scale has a total resistance of 3000,000 ohms, using ohms law l=E/R or 1V/1000 ohms = 1 MADC
OHMS Per Volt
Indication of the total terminal resistance of an analog voltmeter. A measure of the sensitivity of an analog voltmeter. A 1000-ohms-per volt instrument has resistance of 150,000 ohms on its 150 volt (full scale) range, and 300,000 ohms on it 300 volt range. Its basic movement is a 1-milliampere meter (1 = E/R = 1/1000 = .001A = 1 milliampere).
An isolation device that provides an electrical barrier between related circuits.
The excel load beyond full-scale value that an instrument can withstand without damage or failure. Expressed as a percent of a full-scale value.
In digital meters, a reading that exceeds full-scale (but is less than an overload) that does not require switching to a high range, i.e., for 31/2 digit DPM 0-999 is full-scale rating. 1000-1999 is over range. 2000 and up is overload.
The ratio of the overtravel of the pointer beyond a new steady deflection to the change in steady deflection when a new constant value of the measured quantity is suddenly applied.