OS-270 Resistance Decade Box / RTD Simulator

  • The revolutionary ohmSOURCE Microprocessor Controlled Resistance Decade Boxes are like nothing you have ever seen before!
  • Two cost-effective models available
  • Accuracy's as tight as 0.01%, with resolution of 0.01Ω
  • Engineered as an ideal RTD Calibrator
  • Resistance Range ≈ 1 Ω - 1.5 MΩ
Priced at


Microprocessor-controlled and loaded with innovative features, the ohmSOURCE Programmable Resistance Decade Boxes /RTD Simulator succeeds in providing highly accurate and precise resistance values in an intuitive and user-friendly fashion. With a resistance value range of up to 1.5 MΩ and a power rating of up to 1 Watt, the handheld ohmSOURCE decade boxes are practical for all industries including automotive, medical, test and measurement and telecommunications.


Keypad Interface Enter resistance values using a calculator-style keypad.

Quick Value Keys: store/recall up to four frequently used resistance values with one touch. User-definable. Recall up to four frequently used resistance values with one touch.

Memory Keys: Store resistance values in up to 10 additional memory locations (0-9).

Translation Tables (Optional RS-232 interface connection required Part Number OS-91.001) Up to 4 numeric tables allow conversion from your units to a resistance value. Each table holds up to 255 entries; each entry contains your value and an associated resistance value. Your entries represent any type of curve; RTD, thermistor, thermocouple, strain gauge

Current Limiter Limits the amount of current passing through the decade box to prevent possible damage.

Open Key: Conveniently 100% mechanically isolate the ohmSOURCE from the application with the touch of a key.

Increment Value Setting Change resistance by user-defined increments or select standard resistance values (1%, 5%, 10%)

Automatic Eliminates Residual Resistance - the OS-270 residual resistance is automatically factored out in output resistance value

Sensor simulation dual display operation being one of the key features, once programmed for your sensor of choice the unit of measure along with the resistance is viewed simultaneously on the graphic screen: Platinum Resistive Temperature Devices (RTD, PRTD), Negative temperature coefficient (NTC) Thermistors, Conductivity, Strain gauges, Potentiometric sensors (position, level)


≈ 1 Ω to 24  MΩ  
≈ 1 Ω to 1.5 MΩ  
0.1 Ω 
.01 Ω  
Accuracy (no zero subtraction required) 
±0.5 Ω, for 1 kΩ and under ±0.1%, for over 1 kΩ
±0.1 Ω, for 1 kΩ and under ±0.01%, for over 1 k
Power Rating  
1.0 W  
1.0 W  
Power Supply  
4 AA alkaline batteries  
4 AA alkaline batteries  
7.68 x 4 x 1.75 in: 1.1 lb
7.68 x 4 x 1.75 in: 1.1 lb