Inductance Analyzers - 3255BL 3255B 3255BQ

  • Frequency ranges from 20 Hz to 1MHz
  • Fast measurement speed - up to 20 measurements per second
  • 0.1% basic accuracy
  • Up to 125 A of DC bias current
  • Comprehensive measurement functions
  • Straightforward intuitive operation
  • Print test results
  • GPIB control with LabVIEW driver

3255B and 3255BQ are highly versatile and accurate inductance analyzers able to characterise devices in a clear and simple manner. The three  models in the range are the 3255BL (200kHz), 3255B (500 kHz) and the 3255BQ (1 MHz).

At the design stage of component development it is very important to analyse how components performs under different operating conditions. This includes operation over a range of frequencies, AC drive levels or DC bias currents.

The AC drive level can be set between 1 mV to 10 V. DC bias current can be set from 1 mA to 1 A internally (optional) with external DC bias units available increasing the maximum current to 125 A (3255B and 3255BQ).

Specification summary

Measurement functions Z, , L, C, Rac, Rdc, Q, D, turns ratio
Frequency ranges 20 Hz to 200 kHz (3255BL)
20 Hz to 500 kHz (3255B)
20 Hz to 1 MHz (3255BQ)
Basic accuracy 0.1%
Modes Impedance
Multi frequency
Bin handler (option)
DC bias current 3255B and 3255BQ 1 mA to 1 A (internal option)
Up to 125 A when used with five external 3265B/25A DC Bias Units
DC bias current 3255BL 1 mA to 1 A (internal option)
Up to 50 A when used with five external 3265B/10A DC Bias Units
Interface GPIB (option)
Measurement speed Up to 20 measurements/sec

Printed output of test results

Using the parallel Centronics interface the user can directly print all test results for further analysis and archiving.

In addition, via the optional GPIB interface, the instrument can be controlled from a PC and results can be read back for analysis and storage.

LabVIEW drivers are available upon request or may be downloaded from this website providing a base from which a user can develop a specific test application.

Bin sort

The binning function allows component manufacturers to sort components in up to ten bins. Sorting is carried out either by absolute values or by percentage of values.

Component tests with up to 125 A DC bias current

3265B/25A DC Bias Unit can deliver up to 25 A of DC bias current in steps of 0.025 A

The 3255B and 3255BQ enable components to be measured at up to 125 A when multiple external 3265B/25A DC Bias units are used. Extended DC bias capability is also available with the 3255BL which uses the 3265B/5A or 3265B/10A to extend the DC bias current available to 50A.

Up to five of the DC Bias Units can be used in parallel to give a wide range of DC bias currents.

The 3255B Inductance Analyzer can optionally provide an internal DC bias from 1 mA to 1 A.

The 3265B has a number of safety and protection features including a safety interlock system to protect users against back EMFs. It is also fully protected against over temperature, excess voltage drop and sense lead failure.

SMD inductor tests up to 50 A

1009 DC Bias Fixture enables currents up to 50 A to be applied to an SMD inductor

With the addition of the 1009 DC Bias Fixture DC bias currents up to 50 A can be applied  to an SMD inductor during component test in order to evaluate the devices thoroughly at the operational bias currents. The fixture operates with either one or two 3265B/25A Wayne Kerr DC bias units and a 3255B Inductance Analyzer. If two 3265B/25As are used then the optional 5-328-2005 high current lead set will be required.

Four rear panel mounted BNC connectors and two captive high current cables ensure simplicity and ease of use with the 3265B.

Interchangeable component test carriers ensure that the 1009 DC Bias Fixture may be used with a wide variety of devices. If a device package is not supported by one of the standard carriers then a custom carrier design service is available.

Stable component fixturing ensures high accuracy and repeatable measurements. Enclosed fixtures, with safety interlocks, minimises risk to operators.

Technical specifications

Operation modes
Impedance mode
Inductance (L), Impedance (Z), DC Resistance (Rdc) and Capacitance (C).
Series or parallel equivalent circuit
Loss term: Quality factor (Q), Dissipation factor (D), AC Resistance (Rac) and Phase Angle () Turns Ratio
Percentage difference mode and relative mode on major terms.
Multi-frequency mode
Measurement parameters and test conditions set using measurement mode. Up to eight frequencies with absolute or percentage limits on major term with PASS/FAIL indications.
Test conditions
Low level AC drive
For measurement of L + Q, Ls + Rs, C, Z, Turns Ratio
Frequency ranges
20 Hz to 200 kHz (3255BL)
20 Hz to 500 kHz (3255B)
20 Hz to 1 MHz (3255BQ)
At least 800 frequency steps are available which may be selected via the keypad or GPIB.
Basic accuracy of selected frequency 0.01%
Drive level
Source impedance 50 Ω
1 mV to 10V rms into open circuit
50 A to 200 mA rms into short circuit

Automatic Level Control (ALC) maintains level applied to DUT at 2%, 1 mV of set voltage or 2%, 0.1 mA of set current, reduces to 4% below 100 Hz.
DC bias current (option)
1mA to 1A DC is available from internal, fast settling bias supply over full frequency range.
Voltage compliance 14 V minimum
DC Accuracy 2% 0.25 mA
Enabling DC bias inherently reduces measurement accuracy.
Safety interlock minimises operator exposure to high currents.
DC resistance
Low test level of 100 mV minimises heating of the device under test.
Short circuit current 10 mA.
Bin handler mode (option)
Sort to 1 of 10 bins using absolute or percentage limits.
Separate Pass/Fail output.
Up to 100 bin limit set-ups stored in non-volatile memory.
TTL interface to external bin handler via 25 way D type connector.
Measurement speeds
For Impedance, Turns Ratio, DC Resistance
4 speeds selectable for all functions: MAXimum, FAST, MEDium and SLOW.
Maximum for remote control.
Up to 20 measurements per second for test frequency >100 Hz.

Selecting slower speeds improves accuracy and display resolution.
Measurement ranges
R 0.05 mΩ to >2 MΩ
L 1 nH to >1000 H
C 0.01 pF to > 250 mF
Rdc 0.5 mΩ to 50kΩ
Turns Ratio 100:1 to 1:100
L/C/Z/Turns Ratio 0.1%
Q 0.1% (Q+1/Q)
D 0.001 (1+D2)
Rdc 0.5% 1mΩ

Note: Ranges and accuracy vary with measurement speed, frequency and options chosen.

General data
Input specification
Power supply
230 V AC 10% or 115 V AC 10% (selectable) 50 to 400 Hz
150 VA maximum consumption
High contrast monochrome LCD 320 x 240 dot with back lighting.
Visible area 115 x 86mm.
Viewing angle 45
Measurement connections
4 front panel BNC sockets
4-wire (Kelvin) measurements with screen at ground potential
Equivalent circuit symbols on screen
Remote control (option)
Conforms with GPIB IEEE-488.2 and SCPI 1992.0
Printer output
Centronics/parallel printer port
Environmental conditions
Temperature range
Storage -40C to +70C
Operating 0C to 40C
Full Accuracy 15C to 35C
Altitude up to 2000m
Relative humidity: up to 80% non-condensing
Installation category: II (in accordance with IEC664)
Pollution degree: 2 (mainly nonconductive)

This equipment is intended for indoor use only in non-explosive, non-corrosive atmosphere.
Complies with the requirements of EN61010-1
Complies with EN50081-1, EN50082-1 generic emissions and immunity standards by meeting with the requirements of EN55022, IEC801.2, IEC801.3 and IEC801.4
Mechanical (approx. overall)
Height 150 mm (6″)
Width 440 mm (17 3/8″)
Depth 520 mm (20 1/2″)
Weight 11 kg (24 lbs 4 oz)

Order codes and options

3255B Inductance Analyzer 200 kHz
Supplied with user manual and power cable.
3255B Inductance Analyzer 500 kHz
Supplied with user manual and power cable.
3255BQ Inductance Analyzer 1 MHz
Supplied with user manual and power cable.
1 mA to 1 A internal DC bias add /A to part number
GPIB (IEEE-488) interface add /B to part number
Bin handler add /D to part number
Auxiliary units
25A DC bias unit 3265B
(3255B & 3255BQ only)

Supplied with user manual, power cable, spare fuses, 4 x BNC to BNC links, daisy chain link, rack mounting ears (unit needs rear support) and bus bars.
10A DC bias unit 3265B
Supplied with user manual, power cable, spare fuses, 4 x BNC to BNC links, daisy chain link, rack mounting ears (unit needs rear support) and bus bars.
5A DC bias unit 3265B
Supplied with user manual, power cable, spare fuses, 4 x BNC to BNC links, daisy chain link, rack mounting ears (unit needs rear support) and bus bars.
1009 DC Bias Fixture   1J1009
High current lead set for 1009 5-328-2005
Rack mounting kit, 3U x full width 1EXA20230
Kelvin clips (fine jaws). 1EVA40100
Kelvin clips (large jaws) 1EVA40180
4-terminal lead set 1EV1505
SMD Tweezers 1EVA40120