Jandel HM21 Test Unit

Jandel Engineering Limited offers the HM21 for use in making four point probe measurements. The HM21 has six constant current settings between 100nA and 10mA, and measures voltages from 0.01mV to 1250mV.

For sheet resistance measurements, the quoted range is 1 ohm/square to 10 Megohms/square. Measurements outside this range are possible but with possible reduced accuracy.

For volume (bulk) resistivity measurements the quoted range is 10 milliohm.cm to 10 Kohm.cm. Measurements outside of this range may be possible but will depend on sample type e.g. whether the sample is a thin layer.

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    Measurement range1 ohm/square - 10 Megohms/square, 10 mohm.cm - 10 Kohm.cm
    UnitsmV ohm/square
    Onboard Memory50 measurements
    SoftwareFor operation and data control. Supplied free of charge
    Current100nA - 10mA. Reversible to verify contact and measurement
    Accuracy0.5% across range against resistors, better than 0.2% in mid range

    Unit selection

    Measurements can be displayed on screen as mV or ohms/square.

    Computer connection and software

    The HM21 can be connected to computer by USB connection. The customer can operate the unit using the computer keyboard, terminal emulation software such as HyperTerminal, or with the free software provided.

    Want to know more?

    If you require any further information or have an enquiry contact us

    Product FAQs

    Who is Jandel Engineering Ltd?
    Jandel Engineering was established in 1967. Prior to founding Jandel Engineering, Managing Director John Clark worked for A & M Fell in London. It was at this company that the first commercially available four point probe head, the 'Fell' probe head, was designed by John Clark and a colleague. Since this original design many improvements have been introduced.
    Who makes Jandel's probes?
    Experts! All probe heads are made by experienced engineers with a minimum of five years intensive training. Some of our probe builders can boast over 20 years experience.
    What are 'ohms per square'?
    The unit of measurement when measuring the resistance of a thin film of a material using the four point probe technique. It is equal to the resistance between two electrodes on opposite sides of a theoretical square. The size of the square is unimportant and so strictly the measurement is in ohms, however ohms/square distinguishes measurement of a thin sheet from measurement of, for instance, a wire.
    What are 'ohms-centimetre'?
    The unit of measurement when measuring the bulk or volume resistivity of thick or homogeneous materials such as bare silicon wafers or silicon ingots, using the four point probe technique.