The “Electrode Check” port on the front panel of MP3X units is used to measure impedance.
As a rule of thumb, impedance levels below 10 kOhms are ideal, and the lower the better.
Circuit Detail: The “Electrode Check” circuit injects a low current 30Hz sine wave into the “+” and “-” connectors of the SS1LA or SS2L leads.
The circuit is able to measure the Voltage Peak to Peak (V P-P) between “+” and the Ground electrode, as well as between “-” and the Ground electrode. The voltage will vary depending on the resistance between the electrodes. The more resistance, the more the voltage measured.
The circuit is also able to temporarily remove the input connections, in order to determine the voltage in a high impedance state. This allows an auto calibration to be performed without requiring the user to remove the cable from the “Electrode Check” connector.
The calculated resistance (calculated by the hardware/software/firmware) is displayed on the screen when you choose MP3X menu > Electrode Checker.
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