Select Page

PRS-801B Resistance System

  • Accurate Wide Range Resistance Measurements: 0.01 Ω to 2.0×1014 Ω with overall nominal accuracy <±5%; Maximum range 2.0×1014 Ω
  • Variable Voltage 0.1 mv to 9.99 V for low resistance measurements
  • Constant Test voltages 10V and 100V for specification measurements to meet international and domestic ESD measurement standards
  • Auto Resistance Range Control
  • Auto Test Voltage Control
  • Uses rechargeable Li-ion batteries
  • 999 Data Point Memory
  • Download to Excel® in batches or individual measurements with Prostat Connect 2.0

Technical Specs


Wide Range. Accurate. Portable.

The widest range portable constant voltage resistance instrument in today’s market, the PRS-801B is the choice of most ESD professionals. Why? Because the PRS-801B has an outstanding performance combination of measurement speed, wide range and accuracy.Its constant test voltage system is extremely stable and consistent with lab level, bench top instruments.

Measurement Range

The PRS-801B’s wide range offers the maximum flexibility in measurement applications. In effect, it is 3 instruments in one because it functions as:

  1. A low resistance range instrument for measurements from 0.01 to 1.0×104 ohms. Most competitive instruments do not measure accurately at or below 1.0×103 ohms. Thus, the typical ESD practitioner must carry a DMM for low resistance checks of ground connections. To ensure-field accuracy, the PAS-853S Test Lead Shunt is used to remove any resistance in the test leads and get the most accurate reading.
  2. Wide range audit instrument to meet ANSI/ESD S20.20 and TR53 procedures from 1.0×103 to 1.0×1011 ohms. Measurement guidelines require accurate measurements from one decade below to one decade above the resistance requirements of a facility’s ESD program. The PRS-801B easily exceeds this requirement by as much as 3 decades, depending on program requirements.



  1. Precision high resistance measurement instrument for Packaging to S541 Standards, material and product testing and acceptance verification. Few competitive instruments can measure accurately up to or beyond 1.0×1011 ohms, while the PRS-801B comfortably measures up to 2.0×1014 ohms. There are no audit instruments or laboratory bench top instruments that perform in the PRS-801B’s wide range.



Measurement Flexibility

Connect to Virtually any 2-wire Fixture or electrode configuration. The PRS-801B’s simple ¾ inch terminal spacing provides connectivity to a variety of electrodes and fixtures.

  • Terminal design allows use of mechanically shielded or non-shielded banana plug leads
  • BNC adapters with ¾ inch spacing mount directly to the PRS-801B terminals for measurements with wide range probes and fixtures
  • An instrument reference allows use of a third wire instrument reference to minimize effects of extraneous fields on precision fixture measurements



Measurement Speed: Electrification Period

The PRS-801B is one of the fastest measurement instruments in today’s precision measurement market. Laboratory tests confirm the PRS-801B can measure from 0 to 1.0×1012 ohms in 2.5 seconds. Thus, its specified electrification period (EP) is 15 seconds in accordance with ANSI/ESD STM 11.11 Surface Resistance of Planar Materials. Furthermore, its EP is automatically adjusted to insure a stable measurement is displayed.


Multiple Modes of Operation

The PRS-801B has Automatic, Manual, Auto-Manual and Continuous operational modes, plus exponential display or standard numeric display in Ω, KΩ, MΩ, GΩ and TΩ. It’s easy to use and read. Measurements are summarized in decades using multiple LED’s from <102 to >1014, whose colors are user programmable to be RED, GREEN or YELLOW/ORANGE.

Constant Test Voltages

PRS-801B has three Test Voltages ranges that provide stable test references for repeatable measurements. In AUTO mode, the instrument automatically selects the proper test voltage for the resistance being measured.

  1. <10 Volts: 0.01 to 9.99x103 Ω <10V is variable across this range from 0.1 mV to 9.99V
  2. 10 Volts – Constant Voltage under Load Constant at 1.0×104 to 9.99×105
  3. 100 Volts – Constant Voltage under Load Constant at 1.0×106 to 2.0×1014



High Quality Test Leads

Prostat’s 10 foot test leads supplied with each PRS-801B consist of hundreds of fine strands of copper that offer flexibility and accuracy. The outer insulation of each test lead is high grade silicon with an extremely high resistance to minimize measurement errors. These leads are designed for convenient audit measurements in the manufacturing environment up to 1.0×1012 Ω.The 30 inch high performance test lead harness is designed for PRS-801B precision high resistance measurements in the 1011 to 1014 range. It includes a shielded (-) negative test lead for accuracy and minimum electrical interference from personnel and equipment. The shield is connected directly to the PRS-801B instrument reference and fixture ground.


Direct Data Download with Included Software

Not only does the PRS-801B make accurate measurements quickly, it documents measurement data immediately or in batch downloads to your Excel® Spreadsheet program. This minimizes transposition mistakes and speeds up precision measurements. The included Prostat CONNECT 2.0 software is easy to load and use. The PRS-801B connects to your computer’s USB port using the provided USB cable.

  • In the Auto Connect mode, you can control the PRS-801B measurement sequence so that each data point is downloaded to the spreadsheet at the conclusion of each measurement. The Spreadsheet cursor automatically moves to the next data entry cell in preparation for the subsequent measurement.
  • Once as many as 999 data points are stored in the PRS-801B’s memory, they can be downloaded to a spreadsheet at a later time. Each data point will be placed in its own spreadsheet cell.
  • When CONNECT 2.0 is used, a backup Text file is maintained for every measurement set, its date, time and location should you desire.
  • The CONNECT 2.0 utility is compatible with 32-bit and 64-bit version of Windows from XP all the way to Windows 10.

Technical Specifications


Resistance from 0.01 (1.0E-2) Ohms to 200 Tera ohms (2.0E+14 ohms). Maximum Resistivity with ANSI/ESD STM S11.11 concentric ring 2.0E+15 ohms/square.


Automatic Mode (Default): 0.01 volts to 10 volts Variable 1.0E-1 to 1.0E+4 Ohms

Constant Voltage:
10 volts: ± <0.2 volts 1.0E+4 to <1.0E+6 Ohms 100 Volts: ± <2.0 volts 1.0E+6 to 2.0E+14 Ohms Manual Mode: 0.01 volts to 10 volts Variable 1.0E-1 to <1.0E+5 Ohms 10 volts: ± <0.2 volts 1.0E+2 to 1.0E+9 Ohms 100 volts: ± <2.0 volts 2.0E+5 to 2.0E+14 Ohms


Overall: ± <5% at ambient conditions (at 23°C and 30% Rh).Nominal Range Tolerances: 1.00E-2 to 1.00E+1Ω: ±10% corrected for test lead resistance 1.10E+1 to 9.99E+10Ω: ±2.0% 1.00E+11 to 9.99E+11: ±5.0% 1.00E+12 to 2.0E+14Ω: <20% with grounded, shielded lead


Multi-function 2-5/8” x 1-5/8” Liquid Crystal Display with 0.5″ digit height.
Displays 3-1/2 digits in Ohms, or 1.0EXX in exponential format.
Ohms Display indicators: Ω, KΩ, MΩ, GΩ and TΩ. Includes 19-segment analog scale (1-10 with 0.5 indication) with x1, x10, & x100 multipliers.
Number of Data Points in Memory (0 – 999).
Automatic Electrification Time (seconds), or Time required to Manually obtain steady state measurement.
Displays data HOLD, BATTERY status, MIN, MAX, AVG, REC and Test Voltage (<10, 10, or 100 V)


14 Color LED’s from <102 to >1014 ohms.


Times measurements in Seconds up to 999 seconds (Displayed on LCD)


Register stores up to 999 data points


Resistance Range Electrification Period
0.01 to <1.00E+06 Ohms 3.0 seconds
1.00E+06 to <1.00E+12 8.0 seconds
1.00E+12 and greater 180 seconds

Note: Electrification period varies based on conditions & material stability.


Li-ion battery pack, rechargeable via USB. Nominal battery life 120 hours in Continuous Mode


4.5″ wide x 7.5″ long x 2.0″ deep.


18 ounces


<4 ma @ 100 Volts


Select Resistance Range in single decades in Manual and Automatic/Manual modes.


Select Test Voltage of <10, 10 or 100 volts in Manual Mode


Turns Memory Register ON if OFF. Provides access to all data in Memory Register.
Calculates and Displays Minimum, Maximum and Average of data stored in Memory Register.


Erases all data in Memory Register


Power down if ON.


Clears HOLD and Display.


Begins measurement sequence.


Auto Mode:
The instrument automatically selects and adjusts test voltage, resistance range, electrification period, then displays and Holds the measurement. The displayed measurement is the average of eight consecutive measurements, all within ±5% of each other. The measurement is “saved” in the Memory Register by pressing RESET. The instrument is now ready for the next measurement.

Manual Mode:
Allows operator to select resistance decade, test voltage and electrification period (EP).

Automatic Manual:
Same as Auto Mode with following exceptions:

– Allows operator to select starting resistance decade

– Always starts measurement from the last measurement value without resetting to zero. This extends battery life & speeds up measurement sequence.


In RECORD mode, the PRS-801B stores up to 999 measurements, and on demand will calculate and display the Minimum, Maximum and Average measurements stored in the register. Using its USB output and cable accessory, the PRS-801B will communicate with computer USB ports. The PRS-801B will upload data via the Connect 2.0 Utility, which can be used to enter the data in Excel®.