If you do not require as great a measurement range as the RM3-AR Test Unit provides, you might be interested in the:

SRM Probe Head combined with HM21-SRM Hand Held Meter.

General Purpose Four Point Probing System for Measuring Sheet Resistance or Volume Resistivity

SRM Probe Head Combined with RM3-AR Test Unit 

About the SRM Probe

The SRM probe is a lower cost plastic bodied probe that is suitable for use in measuring a wide range of materials including various conductive coatings, ITO on glass, silicon wafers, ingots, potscrap, conductive paints, and various thin films. The connection to the probe head is made via a female RJ45 connector which is the same type of connector used for Ethernet connections. In this configuration, the RM3-AR is supplied with a 1 meter long cable that plugs directly into the SRM probe head.

Holding a probe head by hand does not always work well when measuring higher re-sistance materials and films, however, for many materials it is suitable. Since the probe does not have a switch to control the flow of current, it is best to switch the RM3-AR into the standby mode until the tips are placed into contact so that sparking does not occur as the probe tip approach the material to be tested.

The SRM probe heads are available in three choices of tip spacing, three choices of spring load, two choices of tip material, and three choices of tip radii.

The RM3-AR Test Unit is a specialty electronics instruments designed specifically for the four point probe measure-ment. It features high accuracy, an excellent range, and many features which simplify the four point probing measurement. The following are features of the RM3-AR Test Unit:

• The measurement range of the RM3-AR Test Unit is from 1 milliohm-per-square (10^-3) up to 5 x 10^8 ohms-per-square with 0.3% accuracy. The volume resistivity range is from 1 milliohm-cm (10^-3) up to 10^6 ohms-cm.
• The RM3-AR includes PC control software which can be used for data logging (storing data in the CSV format) and measurement conversion to ohms-per-square or ohms-cm.
• The RM3-AR reads-out directly in ohms-per-square (or toggle to millivolts) without requiring the use of the software or a PC.
• The RM3-AR has onboard non-volatile memory so that up to 50 measurements can be stored internally and then downloaded and saved all at one time using the software. Alternately, each measurement can be saved to a PC as it is made.
• The RM3-AR has an auto-range button that can be used to automatically determine the optimum input current for a given material without using the trial and error method.
• The RM3-AR has forward (FWD) and reverse (REV) buttons to reverse the direction of current flow. A common way to determine if a measurement is valid is to reverse the direction of current flow and then check to see if the forward and reverse voltage readings correlate well, i.e., the values should be similar, but with the reverse current voltage being a negative value.

Specifications:

Features:

Four-Point-Probes is a division of Bridge Technology. To request further information please call Bridge Technology at (480) 988-2256 or send e-mail to Larry Bridge at: sales@bridgetec.com