High-resistance measurement with the 3237, 3238, and 3239

QI use the 3237, 3238, and 3239 to perform high-resistance measurement, but at and above 5 MΩ measured values vary widely. Is the instrument broken?


The instrument may be set to the wrong power supply frequency. This can have a pronounced effect during high-resistance measurement. Precaution concerning high-resistance measurement: Since this type of measurement is susceptible to the effects of external noise, shield the red leads and the measurement target and connect the shielding to the instrument’s COM terminal.