Vishay secondary standard resistor

Vishay has introduced a secondary standard resistor for laboratory calibration standards and digital multimeters.

For test equipment designers, the foil resistors offer high accuracy of 10 ppm at the terminals, long-term stability of ±0.0005% (5 ppm) at +25°C for one year, temperature coefficient of resistance to ±0.3 ppm/°C from 15-45°C (max TCR: 10 ppm to 30 ppm total deviation over temperature range) and resistance tolerance to ±0.005% (50 ppm).

Offering a direct plug-in device for most DMMs, the device is based on a new design using bulk metal foil technology, resulting in a combination of standard features with capabilities for accuracy, stability and speed.

By using these precision resistors instead of the inductive types featured in most secondary standard boxes, the resistors allow for controllable accuracy at the box terminals through calibration, while extending the frequency range up to 10 times.

The devices offer virtually infinite resolution in resistance setting and readability and are available with up to six significant digits (eg, 9.99962) and a wide resistance range from 1 Ω to 150 kΩ, with any resistance value within this range available at any tolerance. For increased reliability, the resistors are contained in an RF-shielded case and a hermetically sealed resistive element eliminates the effects of humidity.

There is a rise time of 1.0 ns, with effectively no ringing, a thermal stabilisation time of <1 s (nominal value achieved within 10 ppm of steady state value), current noise of 0.010 µVRMS per volt of applied voltage (<-40 dB) and a voltage coefficient of <0.1 ppm/V.

The devices offer a non-inductive (<0.08µH), non-capacitive design and are capable of withstanding electrostatic discharges to at least 25 kV without degradation.