The N4L range of frequency response analyzers can be used in a wide range of applications, in reflection of this we have developed various accessories to enable accurate, reliable and convenient measurement.
Injection Transformers

The PSM1700 and PSM1735 feature ground referenced generators, as a result there is a requirement to isolate the injected perturbation signal from ground so that the feedback loop is not shorted to the ground plane. This action is performed by an injection transformer and N4L have designed numerous injection transformers to meet a range of frequencies and voltages.
Model | Frequency Range | Voltage Rating | Turns Ratio | Connectors | Datasheet |
---|---|---|---|---|---|
Standard Injection Transformer | 10Hz to 200kHz | 50V | 6.3:1 | BNC Input, Isolated BNC Output | PSM Injection Transformer Range – Datasheet |
HF Injection Transformer | 500Hz to 35MHz | 50V | 2.3:1 | BNC Input, Isolated BNC Output | |
HV Injection Transformer | 5Hz to 15MHz | 1KV CATII | 2.3:1 | BNC Input, 2x 4mm Safety Connector Output | |
Low Frequency Injection Module | DC to 100kHz | 600V CATII | 3.1:1 | BNC Input, 2x 4mm Safety Connector Output |
Impedance Measurementres
LCR Active Head

The LCR Active Head converts the PSM1700/PSM1735 into a High Performance LCR Meter with true 4-Wire connections that are taken directly to the component without the need for external shunts. Buffering, amplification and selectable shunts provide LCR measurement over a wide frequency and impedance range.
Frequency Range | 10μHz to 5MHz |
Inductance | 100nH to 10kH |
Capacitance | 10pF to 1000μF |
Resistance | 10mΩ to 100MΩ |
Basic Accuracy | |
PSM1700/35 | 0.2% < 1kHz |
PSM1700 | 0.5% + 0.005% / kHz < 1MHz |
PSM1735 | 0.5% + 0.005% / kHz < 5MHz |
LCR Active Head Supplied With: | BNC to Kelvin Clip Lead Set (Power and Comms via hard wired Auxiliary Lead) |
Datasheet | LCR Active Head + IAI/IAI2 – Datasheet |
IAI Kelvin Fixture

The N4L Impedance Analyzer range offers high accuracy, high frequency LCR measurement. To accompany the IAI and IAI2 we have developed an IAI Kelvin Fixture. This fixture features four contact plates providing true four wire impedance measurement.
Frequency Range | DC to 35MHz |
Datasheet | IAI Kelvin Fixture – Datasheet |
IAI 22mm Adaptor

The N4L Impedance Analyzer range are designed with BNC connector spacing that do not match the spacing of some third-party test fixtures on the market. Our IAI 22mm Adaptor converts the standard IAI spacing to 22mm spacing, this simplifies connection to third-party test fixtures with 22mm spacing.
Datasheet | IAI 22mm Adaptor |
Filters
N4L LSF/HSF External Signal Filters

N4L LSF/HSF Filters are a range of filters specifically designed for use with the N4L range of HF current shunts.
Available as 5 kHz low pass and 50 kHz low pass for improved signal to noise ratio.
These compact filters are fitted with safety BNC connectors to enable direct connection to the PPA external inputs.
The HSF10m filter has been designed for DC blocking and is designed to be used in pairs with our BATT470m EIS (Electrochemical Impedance Spectroscopy)
Model | Roll off frequency (-3dB) | Specification Data |
---|---|---|
LSF05 | -3dB@ 5kHz ± 1kHz Low Pass | LSF & HSF – Datasheet |
LSF50 | -3dB@ 50kHz ± 10kHz Low Pass |
|
HSF10m | -3dB@ 10mHz ± 2mHz High Pass |
Electrochemical Impedance Spectroscopy
Batt470m - EIS Interface (Electrochemical Impedance Spectroscopy)

The BATT470m electrochemical impedance analysis interface (EIS) provides an easy to use battery/cell impedance test platform for the electrochemical industry. Utilizing the highly accurate PSM3750 frequency response analyzer from N4L, the BATT470 provides impedance measurement of batteries/cells up to 200V DC.
Datasheet | BATT470m – Datasheet |
Current Measurement (External)
N4L HFR High Frequency Current Shunts

If external current measurement is necessary for impedance measurement, for example if a test setup utilising an LPA Laboratory Power Amplifier for signal generation is employed. The HF series shunts provide an accurate current sensing solution for many wideband measurement applications up to 20Arms. Utilising an innovative design that is unique to N4L, each shunt will maintain its specified resistance over a frequency range from DC to 1MHz without exhibiting the phase shift normally associated with resistive shunts
Model | Current Rating | Specification Data |
---|---|---|
HFR010 | 20Arms | HFR Shunts – PSM – Datasheet |
HFR100 | 6Arms | |
HFR470 | 3Arms | |
HF01R | 1 Arms |
AC Current Clamps

As an alternative to selecting an HFm current shunt for external current measurement in impedance applications is our AC Current Clamp range. These clamps provide current measurement up to 3,000A (P32-UE) with an upper bandwidth of 15kHz (SMUB), providing accurate measurement of an AC signal over a wide bandwidth. Typical applications include impedance measurement of electrochemical cells where high DC current bias is present, the AC responding current clamp will reject the DC bias current and reliable accurate measurement of the AC perturbation current is recorded.
Model | Current Rating | Datasheet |
---|---|---|
M3-UB-50 | 100mA → 50A | M3 UB 50 – 1V |
M3-U-100 | 1 → 100A | M3 U 100 – 1V |
S-UE-200 | 1 → 200A | S UE 200 – 1V |
S-UE-250 | 1 → 250/500/1000A | S UE 250 500 1000 |
US-UE-1000 | 1 → 1,000A | US UE 1000 - 1V |
SM-UE-1000 | 0.5 → 1,000A | SM UE 1000 - 1V |
SM-UB-1000 | 0.5 → 1,000A | SM UB 1000 - 1V |
P32-UE-1000 | 5 → 1,000A | P32 UE 1000 - 1V |
P32-UE-3000 | 5 → 3,000A | P32 UE 3000 - 1V |
High Voltage Measurement
TT-HV-250 High Voltage Probe (2.5kVpk)

For High voltage applications, we recommend the PSM3750 frequency response analyzer, for voltages above this level an attenuator is required and the TT-HV-250 provides measurement up to 2.5kV
Voltage Rating | Attenuation | Bandwidth | Specification Data |
---|---|---|---|
2.5kVpk | 100:1 | 300MHz | 2.5KV High Voltage Probe x1000 – Datasheet |
Ultra Low Capacitance Probe

The ULCP ultra low capacitance probe is intended for voltage measurement of devices which are particularly sensitive to capacitive loading. This is particularly useful when measuring start up characteristics of low power lighting ballasts, the ULCP Ultra Low Capacitance Probe utilises a differential input design that provides a capacitance to ground of 1pF.
Voltage Rating | Attenuation | Bandwidth | Specification Data |
---|---|---|---|
3kVpk, 1kVrms | 1000:1 | 2MHz | ULCP – Ultra Low Capacitance Probe – Datasheet |
TT-HVP-15HF High Voltage Probe (15kVpk, 10kVrms)

The TTV-HVP-15HF High Voltage Probe provides 1000:1 attenuation of voltages up to 15kV, with a bandwidth of 50MHz these probes provide high voltage accurate measurement. For connection advice please contact the N4L application engineering department.
Voltage Rating | Attenuation | Bandwidth | Specification Data |
---|---|---|---|
15kVpk, 10kVrms | 1000:1 | 50MHz | 15KV High Voltage Probe x1000 – Datasheet |
19in Rack Mount Kits
PSM17xx Mounting Fascia Panel
PSM3750 Rack Mount Kit

The PSM3750 rack mount kit consists of two 19in rack mounting brackets providing simple integration into any EIA standard 19in rack system. The brackets are fitted to the Frequency Response Analyzer by removing the two handle fixtures situated on each side of the instrument.
Attenuators

The ATT10, ATT20 and ATT1000 are BNC to BNC voltage attenuators designed for the PSM BNC inputs. They provide high accuracy wide bandwidth gain, typical applications are in situations when the output of a voltage attenuator (such as the TT-HV250) is above the 10Vpk range of the PSM1735 input.
Model | Attenuation | Bandwidth | Max Input Voltage | Specification Data |
---|---|---|---|---|
ATT10 | 10:1 | DC-2MHz | 30Vpk | ATT10 - Datasheet |
ATT20 | 20:1 | DC-2MHz | 60Vpk | ATT20 - Datasheet |
ATT1000 | 1000:1 | DC-10kHz | 1000Vrms | Contact us for information |