Calibration Services

The Laboratory offers calibrations for DC voltmeters rated from 100 µV to 1 kV. Single range voltmeters are normally calibrated at cardinal points (maximum 10 test points). For multi-range voltmeters, the basic calibration will include measurements at full ranges and linearity check at 5 voltage levels for one range. Linearity check for other ranges can be offered at extra cost.

 

The Laboratory offers calibrations for DC ammeters rated from 10 µA to 100 A. The DC ammeter will normally be calibrated at full range in each range.

 

DC current sources/meters at femtoampere level are useful for low-level DC current applications, such as leakage current measurements on electrical/electronic components, mass spectrometer current measurements, probe current measurements in electrochemistry as well as calibration of electrometers, femtoammeters and precision medical equipment.

SCL can provide calibration service for low-level DC current sources/meters ranging from 100 fA to 100 pA.

 

The Laboratory offers calibration service for ohmmeters or resistance meters ranged from 1 mΩ to 10 TΩ.

Single range ohmmeters or resistance meters are normally calibrated at 5 cardinal test points. For multi-range equipment, calibration will be performed at the full range level for all working ranges and linearity check will be carried out at 5 cardinal test points, for one meter range selected by the client.

Calibration for ohmmeters or resistance meters can be performed at any test value within 1 mΩ and 10 TΩ. However, measurement uncertainties will be higher at non-decade valued test points.

 

The Laboratory offers calibration for DC Insulation Resistance Tester with output test voltage not exceeding 1 kV for resistance range from 0.1 MΩ to 600 GΩ or 5 kV for resistance range 10 MΩ to 600 GΩ.

The tester under test will be calibrated against the high-valued standard resistors of the Laboratory. At each calibration point the indication on the tester will be compared with the value of the applied resistance and the output voltage of the tester will also be measured.

As test leads that are used with a tester may have leakage resistance, it is advisable that the client submit these leads for test together with the tester.

 

The Laboratory offers calibration for RCD tester. The calibration service includes the trip time measurement accuracy (10 ms to 1 s), AC residual current output accuracy (5 mA to 5 A), residual pulsating DC current output accuracy (20 mA to 1.406 A) and ramping AC residual current output accuracy(2 mA to 550 mA). The tester under test will be calibrated against an in-house developed RCD tester calibrator, digital oscilloscope and a high precision digital sampling multimeter.

 

The primary function of traditional electrometers is to measure an electrical potential (volts) or charge (coulombs). Nowadays, electrometers are also designed to perform current and resistance measurements.

SCL has been accredited to calibrate electrometers for the following test parameters:

• Electric Charge: 0.1 nC to 2 µC
• DC Voltage: 0.1 mV to 1 kV
• DC Current: 1 pA to 20 mA
• DC Resistance: 1 MΩ to 10 TΩ

(Note:- p, n, µ, m, k, M, G and T are SI prefixes, representing:
p: pico- or 10^-12
n: nano- or 10^-9
µ: micro- or 10^-6
m: milli- or 10^-3
k: kilo- or 10³
M: mega- or 10⁶
G: giga- or 10⁹
T: tera- or 10¹²)

 

Analogue and digital AC voltmeters covering the ranges 1 mV to 1000 V, and 20 Hz to 1 MHz (<2x10⁷ V-Hz) will normally be calibrated against the Laboratory AC voltage calibrators.

AC voltmeters will normally be calibrated at 5 test voltages for one range to establish the scale linearity. For multi-range voltmeters, additional measurements will be made at full range for all the other ranges.

Linearity check for other ranges may be offered upon request at additional charge.

For precision AC voltmeters requiring calibration at very high accuracy, AC-DC transfer technique will be used.

 

The Laboratory offers calibration for withstanding voltage testers / Hi-Pot testers with sinusoidal output voltages (50 Hz) not exceeding 11 kV (r.m.s. value). The calibration will normally include measurement of output voltages and test for leak current detection accuracy. Customers may be required to provide appropriate loading resistors for the leak current test.

For calibration of testers having additional functions, or higher output voltages additional charges will be quoted upon request.

 

The Laboratory offers calibrations for ammeters rated from 100 µA to 20 A (up to 20 kHz) and from 100 µA to 100 A (45 Hz to 60 Hz) using the Laboratory current calibrators.

The AC ammeter will normally be calibrated at 5 test currents for one range to establish the scale linearity. For multi-range ammeters, additional measurements will be made at full range for all the other ranges.

Linearity check for other ranges may be offered upon request.

 

The Laboratory offers calibrations for current clamp meters using the Laboratory current calibrators with a precision 50-turn coil.

The calibration range covers

• DC Current: 400 A to 1000 A
• AC Current at 50 Hz: 400 A to 1000 A

 

The Laboratory offers calibrations for Digital Multimeters (DMM's) with 5-1/2 digits or higher resolutions.

The calibration of DMM's will normally include the tests listed hereunder:

The calibration range covers

1. DC Voltage (10 mV to 1200 V).
   • Measurement at full range for all ranges.
   • Linearity check for one range (usually the basic range).
2. AC Voltage (10 mV to 1 kV, 40 Hz to 1 MHz, < 2x10⁷ V-Hz).
   • Measurement at full range for 3 test frequencies.
3. DC Current (100 µA to 2 A).
   • Measurement at full range for all ranges.
4. AC Current (100 µA to 2 A, 40 Hz to 10 kHz).
   • Measurement at full range for all ranges for 3 test frequencies.
5. DC Resistance (1 mΩ to 100 MΩ).
   • Measurement at full range (decade values) for all ranges.

DMM's up to 7-1/2 digits are normally calibrated against the Laboratory precision DMM's or calibrators.

For DMM's of higher resolutions, or requiring special test specifications or techniques for better measurement uncertainties, calibration charges will be quoted, upon request.