Fiber Optic Isolated Voltage Probe. ISOVP


ISOVP probe with MASTERGAN1 board


The ISOVP isolated voltage probe allows the safe and accurate measurement of floating voltages in power electronic modules or electronics. Although it is best suited for medium voltage equipment due to the isolation provided, the high common mode and EMI rejection make it a perfect choice for general low voltage measurements. The 25V input voltage range with the supplied x10 attenuator is ideal to measure gate voltage in various semiconductor switching devices and study potential problems and improvements. Also input capacitance has been kept to a minimum as this is what really hurts most high-frequency measurements, causing loading of high and medium impedance signal sources and signal degradation.

A calibrate function brings the zero automatically to its position and calibrates the gain of the probe, all this without the need to disconnect the input signal as compared to other probes. A remote standby function allows to safely reduce the power consumption and extend battery life of both probe head and receiver without accessing potentially hazardous areas. The output signal is provided via a BNC connector which allows the use of any 50Ohm input terminated scope. 

The probe head is small enough to be used inside cabinets and small modules. It also features a camera mount type tripod thread that allows easy placement and clearances from the probe to ground to be maintained. 



ISOVP Isolated Probe Brochure
Measurements with the ISOVP Probe Guide
High Voltage Isolated Probe ISOVP User Manual
Probe Accessories
ISOVP Quick Reference Guide


Models Compared

(Coming soon)
Type of probeSplit ProbeSplit ProbeModular Probe
Bandwidth175MHz, 75MHz models175MHz, 75MHz models200MHz
Input range2.5V , external attenuators2.5V , external attenuators20V, 2V (optional), external attenuators
Max. common mode50kV50kV1500V
Remote power-off of probe headYesNoN/A
Fiber cable length2m..12m2..25mN/A
Offset adjustmentFine auto adjustmentFine auto adjustment (with no signal at input)Manual adjustment
Gain adjustmentAuto adjustmentManual adjustmentManual adjustment
Input connectorTouch protected SMBTouch protected SMBTouch protected SMB
OutputCoaxial cable, BNC 50OhmCoaxial cable, BNC 50OhmCoaxial cable, BNC 50Ohm
Tripod mountYesYesYes
PowerReceiver USB powered, Transmitter uses AA batteriesReceiver USB powered, Transmitter uses AA batteriesUSB
Tripod includedYesYesYes
External attenuator includedYes, one to choose (x2, x10 or x50)Yes, one to choose (x2, x10 or x50)No


What are the differences between the ISOVP and ISOVP-L?

The measurements obtainable with both models are the same. However the ISOVP has some features that may be useful for your particular application.

The ISOVP has a bidirectional optical control channel between the emitter and receiver and associated adjustment circuitry. This allows for example a remote standby function by which the probe head is put on standby to save battery while you are not taking measurements. This can be useful in medium voltage applications were reaching the probe head can be hazardous.

The main difference however is in the calibration of the probe. Isolated probes do have offset drift due to temperature changes, so initially after the probe has warmed up a couple of minutes the offset in the ISOVP-L can be automatically corrected with no signal at the input by pressing the CAL button. After that a small long term offset drift may be visible due to temperature changes, although this does not generally have to be the case.

The amplitude adjustment in the ISOVP-L is fixed with a potentiometer and is very stable, but since it is analog it is a bit less precise than the ISOVP. To ease the adjustment of the amplitude we have designed the GEVP-OSC which is a small battery powered oscillator with a precise 2.5V level, setting the scope at 500mv/div the signal should cover exactly 5 divisions.

In the ISOVP both offset and amplitude are adjusted digitally by pressing the CAL button at any time even with a signal connected at the input. This can be useful in applications were more DC accuracy is needed or where you can’t disconnect the input signal because the probe head is inside a high-voltage protection cage.

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