Electrode Impedance Meter D175 (Digitimer)

Digitimer's D175 Electrode Impedance Meter is a compact, portable, and battery-driven device for easy checking of electrode impedances prior to recording or stimulation through surface electrodes on the skin.

When performing electrical stimulation, high electrode impedances can decrease the amount of current that can pass through the target tissue, leading to lower-than-expected stimulation and poor evoked responses. Additionally, high impedances can reduce the signal-to-noise ratio, lowering the signal quality of biosignal recordings such as ECG, EEG, and EMG which rely on low impedances.

The D175 Electrode Impedance Meter is a valuable tool that enables qualified operators to quickly evaluate surface electrode impedances to determine if they are low enough for the intended procedure. The device has green and red bi-colour LEDs that allow the operator to set a threshold impedance at which an LED will light up as red instead of green. This feature makes electrode impedance checking easier by providing a clear indication of "good" (green) or "bad" (red) electrode impedances. The impedance values that the Electrode Impedance Meter can display are 0, 0.5, 2, 3, 5, 7, 12, 20, 30, and 50 kOhm.

The D175 Electrode Impedance Meter comes with 2x AA batteries and an operator's manual.

Note: Important! This product is not a medical device as defined in Regulation (EU) 2017/745. Not designed or intended to be used for diagnosis or treatment of disease.

Features

• Portable and battery-powered
• Easy to use with the press of a button
• Wide impedance range (0-50 kOhm)
• Customisable low/high LED indicators

Technical Specifications

Application Note

To measure the total impedance through a pair of electrodes placed on the skin, the D175 Electrode Impedance Meter passes a small biphasic (charge neutral) current between them. After placing the electrodes on the recording/stimulation sites, connect a pair of electrode lead wires to the RED and BLACK electrode sockets (1.5mm DIN 42802) on the top of the Electrode Impedance Meter. The sockets are colour-coded to help the user identify which electrode is the reference. With the electrodes connected and the Electrode Impedance Meter switched ON (and in METER MODE), the device should display the measured impedance.

Once one or more electrodes with "good" impedance levels have been identified, they can be used as reference electrodes for the remaining ones. If bad/high impedances are found, it may be necessary to replace one or both of the electrodes and follow recommended skin preparation practices.

For display purposes, measured impedances are rounded up to the next highest displayable value. For example, 4 kOhm will light up the 5 kOhm LED. By pressing and holding the Power Button for more than 4 seconds, the Electrode Impedance Meter D175 will enter the SETUP MODE, allowing the operator to adjust the level at which the LEDs illuminate green or red. In SETUP MODE, the LED corresponding to the highest "good" (green) level will flash green. To conserve battery power, the D175 automatically switches off if no button is pressed for over one minute.