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Model 456 - Temperature Controlled Standard Resistor
Isotech, Model 456 - Temperature Controlled Standard Resistor
 
Temperature Controlled Fixed AC/DC Resistors
  • Nominal Temperature Coefficient of Resistance: +0.02ppm/C (with temperature control on)18C to 25C
  • Power Rating: 0.5 watt at +25C
  • Resistance Tolerance (Initial Resistance Accuracy): 0.005%
  • Resistance Range: 5Ω to 3.3 MΩ
  • Current Noise: <0.010V (RMS) / Volt of Applied Voltage
  • Thermal EMF: 0.1V/C Max; 0.05V/C Typical


Product Code: 456
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   Product Description    Specifications
 
By temperature-controlling an otherwise very stable resistor, a performance close to the very best available in the world can be achieved at a surprisingly low price. The resistor itself is oil-filled and hermetically sealed.

The function of hermetic sealing is to eliminate moisture and oxygen, both of which play roles in the long-term degradation of unsealed resistors. A further enhancement in both short and long term stability is achieved by oil-filling. The oil also acts as a thermal conductor, allowing the device to accept short periods of overload without degradation.

With accuracies of 0.005%, a resistance range from 5Ω to 3.3 MΩ, and long term drift of less than 5ppm, these devices are virtually secondary standards that can be kept in a laboratory as references to calibrate other devices.

The Resistor is held in a temperature-controlled environment heated to 300.1C. Other temperatures are available by special order. The heater requires 2 watts at 5V, which can be supplied by a battery or an unregulated DC supply. In an ambient environment of 20C, the Resistor's heater will typically warm up in 30 minutes, and a LED shows when the temperature has been reached. A test pocket is provided so that the resistors' temperature can be monitored if required.

0.1 ppm/month or better stability can be expected.

We can supply the value you choose, 0.1% between a minimum of 5Ω and a maximum of 3.3 megaΩ. However, we bulk buy and keep in stock the following standard values: 10W, 25W, 100W, 1000W, and 10,000W.

For the highest quality traceability, we recommend that the 456 be UKAS Certified. We can offer the 2 Sigma Uncertainties shown in the table.
  • Nominal Temperature Coefficient of Resistance: +0.02ppm/C (with temperature control on)18C to 25C
  • Power Rating: 0.5 watt at +25C
  • Resistance Tolerance (Initial Resistance Accuracy): 0.005%
  • Resistance Range: 5Ω to 3.3 MΩ
  • Current Noise: <0.010V (RMS) / Volt of Applied Voltage
  • Thermal EMF: 0.1V/C Max; 0.05V/C Typical
  • The most precise and stable resistors available
  • Impervious to harmful environments - oil filled
Literature
Model 456
Model 456 Datasheet Model 456 Manual