SRAC Standard Resistors Designed for Use At AC

  • Precision resistance standards designed for use up to 10 kHz
  • Available for values from 1 mΩ - 10 MΩ
  • Bnc option available (add -bnc to end of part number)
  • Contact IET for custom resistance values
  • Very stable <20 ppm/year for most values at ac and dc 
  • ISO-17025 accredited calibration at dc and 1 kHz Included
  • < 25 ppm difference between dc / 1 kHz for resistances ≤ 100 kΩ
  • Excellent temperature coefficient, as low as 1 ppm/°C
Priced at
$0.00

Most precision standard resistors are sealed.  Where sealed resistors are more stable, they have a poor frequency response.
IET has designed and manufactured our SRAC Series which has excellent ac frequency response while maintaining long term stability of less than 20 ppm.

Calibration: Unlike most resistors, where the calibration value is only available at dc, IET Labs provides an ISO-17025 accredited calibration of these resistors at dc and at 1 kHz.  Sweep calibrations and other frequencies are available for a premium. 

Configuration:  Units come standard with 4 gold plated low thermal emf binding posts, plus ground for use in both 2, 3 or 4-Wire kelvin applications.  For a small premium we can make this in any configuration you require including bnc.   

Decade Box: If you are looking for a Decade Resistor with very strong ac performance consider our 1433 Series 

Frequency response  lower resistance, for example, 1 Ω will have a much better frequency response than higher resistance, for example, 10 MΩ

Because calibration uncertainties are much better at dc than ac, IET recommends that for resistance values below 1 MΩ it is recommended to use the dc value for the ac value at 1 kHz. For resistance values of 1 MΩ and 10 MΩ it is recommended to use the ac value.

The frequency response for SRAC values of 100 kΩ and lower is based upon the formula below;

AC Resistors

Model  SRac- Nominal (Ω) Initial adjustment to nominal (ppm) Stability 1 year (ppm) Tempco (ppm/°C) Resistor Type Calibration uncertainty dc (ppm) (typical) dc to ac change at 1 kHz  (ppm) (Typical) Max Power (W) Max Voltage (V) Max Current (A) Terminals 
0.001 0.001 200 50 20 Manganin strip 200 25 0.2 0.015 14 4 bp's + gnd
0.01 0.01 200 50 20 Manganin wire 100 0.6 0.15 4.5
0.1 0.1 100 20 1 Foil 60 0.3 0.17 1.7
1 1 1 10 0.3 0.54 0.54
10 10 2 5 0.6 2.45 0.245
100 100 1 5 24.5 0.024
1K  1 k 1 5 77.5 7.7 mA
10K 10 k 1 2 245 2.5 mA
100K 100 k 1 2 300 2 mA
1M 1 M 5 Wirewound 5 250 0.5 700 0.7 mA
10M 10 M 15 Film 10 2500 0.1 1000 0.1 mA