GenRad 1491 Decade Inductor IET LABS

GenRad 1491 Precision Decade Inductor – IET Labs

High-Accuracy Inductance Standard for Lab and Design Applications

The GenRad 1491 D and G Precision Decade Inductors from IET Labs are among the most accurate commercially available decade inductors, designed for applications that demand reliable and adjustable inductance. These inductance boxes are ideal for use in laboratories, design development, and equipment calibration where precision and stability are essential.

Whether for filter design, circuit tuning, or general R&D, the 1491 series delivers high-Q performance, excellent shielding, and precise step control, making them a dependable standard in test and measurement environments.

Features

• Accuracy up to 0.8%, suitable for precise inductance measurements

• Inductance range up to 11.11 henries depending on model

• Model 1491D: 4 decades, 1 mH steps

• Model 1491G: 5 decades, 100 µH steps

• Shielded toroidal cores reduce external interference and mutual coupling

• Sealed to protect against moisture and ensure long-term stability

• High Q factor (200+), especially effective at low frequencies

• Robust switching system with ceramic stator/rotor and silver alloy contacts

• Positive detent action ensures precise decade switching

Applications

• Design and testing of wave filters, tuned circuits, and equalizers

• Circuit optimization during the prototype stage

• General-purpose lab use for variable inductance applications

• Oscillator circuit tuning and analysis setups

• Educational and training environments for inductance demonstration

Specifications

• Accuracy:

  • Model 1491-D: ±0.8% at 100 mH and 1 H

  • Model 1491-G: ±0.8% at higher inductance, ±2% at lower ranges

• Inductance range:

  • 1491D: 1 mH to 11.11 H (4 decades)

  • 1491G: 100 µH to 11.111 H (5 decades)

• Maximum rated voltage: 500 V rms (recommended maximum 150 V)

• Zero inductance: Approximately 1 µH

• Construction:

  • Moisture-sealed body

  • Shielded toroidal core design

  • High-durability switch contacts

The GenRad 1491 series decade inductors are trusted by engineers and researchers for their superior performance and adaptability. Built for precision and made to last, they are an essential tool for any serious electrical measurement or design lab.