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pH Meter


    The pH Meter is a portable field instrument that measures pH, millivolts, and temperature of aqueous solutions. The pH is a measure of acidity or alkalinity; a measure of 7 being neutral, less than 7 acidic and greater than 7 basic. The pH of a solution is determined by measuring the voltage difference in millivolts between two special electrodes housed at the end of the probe.

Requirements: The portable, rugged pH meter was designed to be used in the field. It may also be used ina  classroom or laboratory setting. It is powered by either a 9V battery or a 9V DC line adapter.

Suggested Grade Levels
: 9th and above
Suggested Courses: Chemistry, Biology, Environmental Science
Video Demonstration:


  1. Perform a set-up and self-test before calibration. Use this procedure before initial instrument operation and whenever troubleshooting is necessary.

    1. Disconnect both plugs of the probe from the meter.

    2. Connect the BNC shorting cap to the sensing electrode input (push it hard). This is the attached rubber cap with a metal pin inside.

    3. Press and hold the YES key while pressing the I/O key. Release both simultaneously to perform the diagnostic test.

    4. After test 7 a "0" will appear on the display. Test the function of each key by pressing each key on the keypad, including the I/O key (the numeric digits displayed will change). The meter will then turn off. Remove the BNC shorting cap and connect the electrode to the BNC and ATC/DIN connections.

  2. Calibrate the pH meter. Perform a one or two buffer calibration before pH is measured. This will help determine if the electrode is working properly.

    1. Choose either 4.0 and 7.0, or 7.0 and 10.0 buffers, whichever is closet to your expected sample range.

    2. Press the MODE key until the pH mode indicator is displayed. Place the electrode into the 7.0 buffer and press the CAL key. CALIBRATE and P1 will be displayed along with values for the calibration slope. Once the meter is stable, the meter will beep and READY will be displayed. Press YES to accept this point.

    3. When P2 is displayed, the meter is ready for the second buffer. Rinse the electrodes and place them in the second buffer. Wait for a stable pH reading, the meter will beep, and then READY will be displayed. Press YES to accept the second point.

    4. The electrode slope will be displayed in mV/pH units. SLP appears in the lower field. The meter will advance to measure mode when MEASURE appears above the main display.

    5. The meter is now ready to take pH measurements. The EC10 retains this calibration until a new calibration is entered or until the power is disconnected from the unit.
SAGE Bristol,
Nov 16, 2011, 12:50 PM
SAGE Bristol,
Feb 7, 2012, 11:12 AM