DC and AC measurements

Instruments for measuring low-frequency (LF) electrical quantities are traditionally present in all segments related to electricity; they are used for education purposes in schools, they are indispensable in repair workshops, they are needed in production lines maintenance as well as in the R&D in all electrotechnical laboratories. Moreover, testing and especially calibration laboratories essentially depend on them.

Development of low-frequency instruments started in 19^th centuries when pioneers like Michael Faraday, Edward Weston, Elihu Thomson et al. invented first galvanometers, voltameters and amperemeters to experiment, measure and study new and yet not well-known phenomena related to electromagnetics and electricity. A significant progress in science and technology and later in industry also triggered a rapid development in complexity as well as in precision of measuring equipment which is today present in kinds of industry like power electronic manufacturing, transportation, medicine, automotive, electronics development, machinery industries, etc. Nowadays, inexpensive handheld instruments measuring AC and DC current andvoltage, resistance, etc. with accuracy typically well below 1% are readily used. Furthermore, the instruments like HP/Agilent/Keysight 3458A, Fluke 8588A reference multimeters, Zener-based DC voltage standards, Fluke 5790A AC measurement standard, and reference shunt resistors are used when higher accuracy in a part-per-million scale is needed for precise measurements in R&D and in calibration laboratories or even to provide measurement traceability to the primary unit definition. In addition, a novel Josephson effect-based standards are used in metrology laboratories to provide state-of-the-art accuracy which typically ranges in parts-per-10¹⁰.

On contrary, the instruments for measuring of RF&MW and especially EMC phenomena are relatively new. Additionally, all physical phenomena’s, parameters and conditions influencing the measurements are not yet very well-known and are often difficult to control, therefore this equipment is generally more expensive and bring typically significantly higher uncertainty which sometimes exceeds 10%.

SIQ provides a broad scope of AC and DC calibration services for almost all types of LF instruments used in different type of industries. Calibrations are usually performed at SIQ or when required also at the customer’s premises (on-site). We perform accredited calibration of the following AC and DC quantities:

• DC voltage up to 1000 V
• DC current from 1 pA to 1500 A
• DC resistance up to 100 TΩ
• DC power up to 20 kW
• DC current up to 3 kA using current clamps, current transformers, or current transducers
• AC voltage up to 1000 V (from 10 Hz to 1 MHz)
• AC current from 1 μA to 100 A (from 10 Hz to 30 kHz)
• AC power up to 70 kVA (from 45 Hz to 850 Hz)
• Phase from 0° to 360° (from 10 Hz to 1 kHz)
• AC current up to 3 kA using current clamps, current transformers, or current transducers (from 45 Hz to 450 Hz)
• individual harmonic components, interharmonics, total harmonic distortion (THD) and flicker, dips, and swells