OS-260 Resistance Box IET LABS

OS-260 Resistance Box – IET Labs

High-Precision, Handheld Resistance Source with Microprocessor Control

The IET Labs OS-260 ohmSOURCE Resistance Box is a compact, handheld device designed to deliver precise resistance values for testing, calibration, and simulation applications. Built with microprocessor control, it offers modern features such as a keypad interface, memory storage, and current-limiting protection, making it an essential tool for engineers and technicians in fields like automotive, medical, telecommunications, and industrial electronics.

With a resistance range of approximately 1 Ω to 24 MΩ, the OS-260 is versatile enough to cover a wide array of applications. It is designed for manual operation and cannot be connected to a computer system, making it ideal for fieldwork or environments that do not require remote programming. For automated or programmable applications, IET Labs recommends the PRS-330 model.

One of the standout features of the OS-260 is its dual-display sensor simulation mode, which can be programmed to display resistance along with real-world measurement units such as temperature, strain, or position — making it useful for simulating RTDs, NTC thermistors, strain gauges, and potentiometric sensors.

Features

• Microprocessor-controlled for accurate and stable resistance output

• Calculator-style keypad for quick and direct resistance entry

• Quick Value keys for storing up to four frequently used values

• Memory keys for storing up to ten custom resistance settings

• Current limiter for circuit protection

• “Open” key to instantly disconnect output

• Automatic zero-resistance compensation

• Programmable resistance increments or standard decade steps

• Dual-display operation for sensor simulation

Applications

• Field calibration and troubleshooting

• Sensor simulation (RTDs, NTCs, strain gauges, conductivity)

• Bench testing of electronic components

• Educational and lab use

• Replacement for conventional decade boxes with enhanced functionality

Specifications

• Resistance range: approximately 1 Ω to 24 MΩ

• Resolution: 0.1 Ω

• Accuracy:

  • ±0.5 Ω for values ≤ 1 kΩ

  • ±0.1% for values > 1 kΩ

• Power rating: 1.0 W

• Power supply: 4 AAA alkaline batteries

• Dimensions: 3.3 x 6.6 x 1.25 inches

• Weight: 1.1 lbs

The OS-260 combines portability, ease of use, and advanced simulation features, making it an excellent choice for precision resistance substitution in a wide variety of industries.