Electrostatic Voltmeters

Many very high impedance (> 1010 Ω) voltage measurements cannot be made using conventional type voltmeters because charge transfer into the voltmeter is required, thus causing loading and modification of the source voltage. For example, when measuring voltage distribution on a dielectric surface, any measurement technique that requires charge transfer, no matter how small, will modify or destroy the actual data. In these types of applications an electrostatic voltmeter is required.

An instrument that measures voltage with virtually zero charge transfer is called an electrostatic voltmeter. A primary characteristic of electrostatic voltmeters is that they accurately measure surface potential (voltage) on devices or surfaces, with or without physical contact.

We are known for our novel non-contacting voltmeter designs, first introduced in 1968, to address charge transfer issues associated with the contacting voltmeter designs at the time. With these non-contacting electrostatic voltmeters an electrostatic voltage monitoring probe is placed in close proximity (1 mm to 5 mm) to the surface to be measured. These electrostatic voltmeters function to drive the potential of the probe body to the same potential as the measured unknown. This achieves a high accuracy non-contacting measurement that is insensitive to variations in probe-to-surface distances and prevents arc-over between the probe and measured surface.

Contacting Voltmeter: Infinitron 820

Contacting Voltmeters: Infinitron 821HH

Non-Contacting Voltmeter: Model 344

Non-Contacting Voltmeter: Model 341

Voltmeter Probe: Model 600B-15C

Voltmeter Probe: Model PD1216P

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Contacting Voltmeters

ModelResistance CapacitanceMeasurement Range (DC or peak AC)Speed of Response (10% to 90%)AccuracyData Sheet
820Infinitron® 8201 x 1015 Ω / 1 x 10-15 F0 to ±2 kV< than 500 µs / for a 1 kV step0.1% of full scale
821HHInfinitron® 821HH1 x 1014 Ω / 1 x 10-14 F0 to ±2 kV< than 500 μs / for a 1 kV step±1% of full scale

Non-Contacting Voltmeters

VoltmeterMeasurement RangeAccuracyAvailable ProbesData Sheet
341B0 to ±20 kV0.1% of full scale3450- 3453ST- 3455ET
P08650 to ±10 kV0.1% of full scale3450- 3453ST- 3455ET
3700 to ±3 kVBetter than 0.05% of full scale3800E 2- 3800S 2- 3870ET 2- 3870ST 2- 7000ER
3470 to ±3 kV0.05% of full scale555P 1- 555P 4- 6000B 5C- 6000B 6- 6000B 7C- 6000B 8- 6000B 13C- 6000B 14- 6000B 15C- 6000B 16- 6300 7- 6300 8
3440 to ±2 kV0.05% of full scale555P 1- 555P 4- 6000B 5C- 6000B 6- 6000B 7C- 6000B 8- 6000B 13C- 6000B 14- 6000B 15C- 6000B 16- 6300 7- 6300 8
706B0 to + or -1 kV0.5% of full scale
3230 to ±100 V0.05% of full scale6000B 8- 6000B 16
320C 0 to ±100 V0.05% of full scale3250
3250 to ±40 V0.05% of full scalePD1216P

Electrostatic Voltmeter Probes

Probe Model and FeaturesVoltmeter ModelBody Shape/ Aperture Location/ SizeDimensions H x L x W (mm)Speed of ResponseNoise (rms)
3250 high-sensitivity320C square / side/ 6.35 mm dia.30.5 x 28.7 x 57.2< 300 ms< 5 mV
PD1216P high-sensitivity325round / side/ 4.6 mm dia.10 dia. x 56 L    < 3 ms< 1 mV
555P-1 miniature344 347square / side/ 2.56 mm dia.5.6 sq. x 49.8 L< 3 ms< 3 mV
555P-4 miniature344 347square / end/ 1.17 mm dia.5.6 sq. x 49.8 L< 4.5 ms< 4 mV
6000B-5C high-resolution344 347round / end / 0.79 mm dia.11.2 dia. x 65.7 L< 4.5 ms< 4 mV
6000B-6 high-resolution344 347round / side / 0.79 mm dia.10.3 dia. x 69.7 L< 3 ms< 3 mV
6000B-7C344 347round / end / 1.32 mm dia.11.2 dia. x 65.7 L< 4.5 ms< 4 mV
6000B-8323* 344 347round / side / 1.32 mm dia.9.5 dia. x 68.6 L< 3 ms< 2 mV
6000B-13C high-resolution344 347square / end / 0.79 mm dia.10.2 sq. x 63.7 L< 4.5 ms< 4 mV
6000B-14 high-resolution344 347square / side / 0.79 mm dia.10.2 sq. x 68.6 L< 3 ms< 3 mV
6000B-15C344 347square / end / 1.32 mm dia.10.2 sq. x 63.7 L< 4.5 ms< 4 mV
6000B-16323* 344 347square / side / 1.32 mm dia.10.2 sq. x 68.6 L< 3 ms< 3 mV
6300-7 high-temperature (to 100º C)344 347square / end / 1.32 mm dia.11.8 x 11.1 x 76.2< 6 ms< 10 mV
6300-8 high-temperature (to 100º C)344 347square / side / 1.32 mm dia.11.8 x 11.1 x 76.2< 4 ms< 10 mV
3450341B P0865square / side / 3.05 mm x 1.52 mm11.8 x 11.1 x 76.0< 200 µs< 20 mV
3453ST high-temperature/ vacuum341B P0865square / side / 3.05 mm x 1.52 mm11.8 x 11.1 x 76.2  < 200 µs< 20 mV
3455ET high- temperature/ vacuum341B P0865square / end / 1.52 mm dia.11.8 x 11.1 x 76.2  < 200 µs< 20 mV
3800E-2 miniature370square / end / 1.85 mm dia.5.6 sq. x 50 L368A < 200 µs / 370 < 50 µs368A < 25 mV/ 370 < 20 mV
3800S-2 miniature370square / side / 2.35 mm dia.5.6 sq. x 50 L368A < 200 µs / 370 < 50 µs368A < 25 mV/ 370 < 20 mV
3870ET-2 elevated-temperature370square / end / 1.85 mm dia.5.6 sq. x 50.0368A < 200 µs / 370 < 50 µs368A < 25 mV/ 370 < 20 mV
3870ST-2 elevated-temperature368A 370square / side / 2.35 mm dia.5.6 sq. x 50.0368A < 200 µs / 370 < 50 µs368A < 25 mV/ 370 < 20 mV
7000ER370round / end / 1.60 mm dia.8.7 sq. x 69.8 L50 µs< 20 mV

* Speed of response and noise specifications may vary from those listed here for Model 323.