Calibration of Eletrical Fast Transients

By Category: EMC/EMI Testing

What are Electrical Fast Transients

The electrical fast transient burst (EFT/B) is generated by the switching of inductive loads.

This switching transient is commonly referred to as fast transient and may be described in terms of:

  • The duration of the burst (which is predominately determined by the energy stored in the inductance prior to switching);
  • The repetition frequency of the individual transients,
  • The varying amplitude of the transients composing a burst, determined mainly by the mechanical and electrical characteristics of the switching contact (speed of the contacts in the opening operation, voltage withstand capability of the contacts in their open condition).

Generally, the EFT/B has no unique parameters that depend upon the characteristics of the switching contact or the switched load.

Reference StandardCalibration Parameter
IEC 61000-4-4 Amplitude, Burst duration, Burst Period, Pulse Rise time, Pulse width, Repetition Rate

Calibration of The Characteristics of Fast Transient/Burst Generator

The test generator characteristics shall be calibrated in order to establish that they meet the requirements of this standard. For this purpose, the following procedure shall be undertaken.

The test generator output shall be connected to a 50 Ω and 1000 Ω coaxial termination respectively and the voltage monitored with an oscilloscope. The -3 dB bandwidth of the oscilloscope shall be at least 400 MHz. The test load impedance at 1000 Ω   is likely to become a complex network. The characteristic of the test load impedance are:

  • (50 ± 1) Ω
  • (1000 ± 20) Ω  the resistance measurement is made at d.c.

The tolerance of the insertion loss of both test loads shall not exceed as follows:

  • ± 1 dB up to 100 MHz
  •  ± 3 dB from 100 MHz up to 400 MHz

Block Diagram of Calibration Set up

Calibration at coaxial 50 Ohm output of the simulator with a 50 Ohm load

Ratio with KW50 -> 1:400

Example: 2000V Burst = 5V on scope

Calibration at coaxial 50 Ohm output of the simulator with a 1000 Ohm load

Ratio with KW1000 -> 1:1000

Example: 2000V Burst = 2V on scope

Specification of calibration

According to standard Parameter and specification.

EFT, 50Ω Load @ 5 KHz

Parameter Lower Limit Nominal value Higher Limit
Amplitude 250-4000V, ± 10 %
Burst duration (ms) 12 15 18
Burst Period (ms) 240 300 360
Pulse Rise time (ns) 3.5 5 6.5
Pulse width (ns) 35 50 65
Repetition Rate (սs) 160 200 240

EFT, 1000Ω Load @ 5 KHz

Parameter Lower Limit Nominal value Higher Limit
Amplitude 240-3800V, ± 20 %
Burst duration (ms) 12 15 18
Burst Period (ms) 240 300 360
Pulse Rise time (ns) 3.5 5 6.5
Pulse width (ns) 35 50 150
Repetition Rate (սs) 160 200 240

EFT, 50Ω Load @ 100 KHz

Parameter Lower Limit Nominal value Higher Limit
Amplitude 250-4000V, ± 10 %
Burst duration (ms) 0.6 0.75 0.9
Burst Period (ms) 240 300 360
Pulse Rise time (ns) 3.5 5 6.5
Pulse width (ns) 35 50 65
Repetition Rate (սs) 8 10 12

EFT, 1000Ω Load @ 100 KHz

Parameter Lower Limit Nominal value Higher Limit
Amplitude 240-3800V, ± 20 %
Burst duration (ms) 0.6 0.75 0.9
Burst Period (ms) 240 300 360
Pulse Rise time (ns) 3.5 5 6.5
Pulse width (ns) 35 50 150
Repetition Rate (սs) 8 10 12

ITC  provides ISO/IEC 17025 accredited Calibration Services for Electromagnetic Compatibility (EMC) Test Equipment. We are doing the testing in EMC/EMI and support your specific regulatory or industry compliance. In addition to calibrations of EMC & EMI testing equipment, our accredited labs offer calibration services for ESD Stimulator as per IEC 61000-4-2:2008, Burst Generator as per IEC 61000-4-4:2012, Surge generator as per IEC 61000-4-5:2014+AMD1:2017 and Voltage dips & short interruption as  IEC 61000-4-11:2020.