Decade boxes and dividers provide highly accurate and digitally variable standard values of resistance, capacitance, inductance, voltage, and/or current for calibration, comparison, and testing. Decade boxes and dividers include decade inductors, decade resistors, decade capacitors, voltage dividers, and precision potentiometers. Automated test equipment (ATE), electrical testing instruments, and other specialized electronic test systems often use decade boxes and dividers as precision components. Voltage dividers and Kelvin-Varley dividers or potentiometers provide a ratio of voltage or current for use as a reference.

Standards

Transfer, primary, and laboratory grade standards are used to compare or transfer accuracies from the National Institute of Standards and Technology (NIST) or other nationally certified organizations to working decade boxes and dividers. Typically, these working devices are robust or rugged units for production or in-line testing and calibration. 

Types

There are several types of decade boxes and dividers.

Standards are devices that usually consist of a single, fixed-value component or several components not in the same circuit. Standards with more than one component (e.g., several fixed value resistors) have multiple posts or a rotary switch for selecting different resistance values.

Substituters, another type of device, usually consist of multiple components. Varying the number of resistors in series or parallel sets the standard resistance value for the circuit.

Voltage dividers are digital potentiometers that provide a highly accurate ratio (V_out / V_in) of voltage and current for calibration and testing.

Kelvin-Varley voltage dividers consist of a bridge circuit with two standard value resistors. RTD simulators provide an output to simulate an RTD resistance value for the calibration and testing of resistance temperature detectors.

Thermocouple simulators output a precise voltage.

Features

Decade boxes and dividers are available with a variety of features. Some devices are suitable for alternating current (AC) or direct current (DC) calibration and testing applications. Other devices are designed for use in larger systems or products, or can perform precision measurements. Rack mounted, stand-alone, and benchtop devices are often available. Low zero or residual decade boxes and dividers have low values of zero, offset, or residual impedance resistance, inductance, or capacitance. Variable decade boxes and dividers can provide a precise and continuously variable value such as a variable capacitor or potentiometer. Devices are also available with a computer interface option for programming, control, or data acquisition.

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Ohmite Manufacturing Co.