Physiological recordings can be easily contaminated by noise and interference. In many cases, high electrode contact impedance is a big part of the problem. Noise often appears as 50 or 60 Hz "hum" from surrounding AC-powered electrical devices or as erratic spikes due to any motion of the lead wires. In virtually every case, these troublesome artifacts can be mitigated or completely eliminated by reducing contact impedance at the skin/electrode interface. UFI's Checktrode™ applied electrode contact impedance testers are designed to help accomplish this task.

Description
Specifications

Model 1089NP Checktrode with Lead Selector

The Model 1089NP evolved from the 1089ES, and has a few important differences. Whereas the 1089ES is a general-purpose instrument, the Model 1089NP is intended for use with several specific electrode caps. These include the Brainmaster Discovery qEEG system cap, the NeuroPulse Systems qEEG cap, the Mistar Systems cap and any standard Electro Cap or Comby Cap used with other qEEG systems.

For ease of use, Model 1089NP rotary selection switch positions are directly keyed to electrode site names for the listed caps. A two-position TEST switch permits the two reference electrodes supplied with these caps to be tested against each other. When good contact between them has been established, just flip the TEST switch to link the two reference electrodes, then check contact impedances of the remaining cap electrodes.

View the user manual here.

1089 general specifications

impedance readout: 3 1/2 digit LCD display
contact impedance range: 0-199 KOhm (custom ranges available)
excitation frequency: 30 Hz (typical)
typical excitation current: 10 uA p-p (constant current)
calibration setting: 50 KOhm
input connectors: 2 each 0.080" and 0.060" safety jacks and 1 male snap (1089)
battery test load: 1 KOhm
power switch: push-button on with auto-shutdown after 5 minutes
rugged plastic case: 6" x 3.5" x 1.5" (Std 1089)

Model 1089 MkIII Checktrode (impedance meter)	Model 1089e Economy Checktrode (Impedance)
Model 1089ES Checktrode (impedance meter)