Types of Metal Electrodes
WPI offers a large variety of metal electrodes and they come in four basic styles (profiles). The selection guide that follows references the four electrode profiles. In addition, concentric bipolar electrodes are also discussed, as well as some of the options offered for the metal electrodes.
NOTE: The electrode diagrams below are not shown to scale.
Profile A
Profile B
Profile C
Profile D
Concentric Bipolar Electrodes
These electrodes are excellent for shielded macro recording, as well as evoked potentials. They are especially well suited for bipolar stimulation. The tungsten electrode is sharpened to a point and is 75μm in diameter. The outer stainless steel conductor is insulated with Polyimide tubing to within 0.2mm of the end of the stainless steel tube. This electrode is also available without the outer Polyimide insulation.
This figure shows an insulated metal conductor with an exposed concentric surface.
♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦
Metal Electrode Options
Exposed Tip Dimensions (nominal)
WPI electrodes made from a variety of metals and tip diameters to offer the nominal impedance ratings you require. Use the table below to determine which type of electrode will meet your criteria.
Nominal
Impedance |
Tungsten
|
Elgiloy
|
Platinum
Iridium
|
Pure
Iridium |
| 0.1 MegΩ |
100µ |
120µ |
60µ |
45µ |
| 0.5MegΩ |
55µ |
66µ
|
18µ |
14µ |
| 1.0MegΩ |
30µ |
36µ |
10µ |
10µ |
| 2.0MegΩ |
12µ |
15µ |
6µ |
5µ |
| 5.0MegΩ |
5µ
|
6µ |
3µ |
2.5µ |
Kapton (KT) Tubing
Kapton* tubing, indicated by “KT” in the part number, extends from the connector to within 5mm of the tip, providing stiffness and additional insulation to the electrode shaft. Kapton-clad electrodes are recommended when the electrode is to be inserted through a cannula for extra deep penetration.
Heat Treated Tip
The Heat Treated Tip (see image below) is ideal for penetrating tough membranes. (It is not recommended for chronic implantation.) This process is performed using a microforge in which the heating element is positioned in close proximity to the tip in order to melt the Parylene-C distal to the exposed metal. It provides a smooth transition and produces better adherence of the Parylene-C to the metal.
To have your electrodes heat treated, just add the suffix “H” to any of the “KT” numbers on the facing page. Cost of the treatment is $10 per package of 10 electrodes ($20 per package for Type B).
* Parylene is a trade mark of Union Carbide. Kapton is a trade mark of DuPont. Elgiloy is a trade mark of Elgiloy Ltd.
Gold Plated Pins
Gold-plated pins (WPI #5482) and sockets (WPI #5483) may be attached to 24-, 26- or 28-gauge wire.
Additional Accessories
300102
|
Micromanipulator holder, 4 in., 2mm to 0.031 socket |
| 5468 |
2 mm receptacle to 0.031-inch jack (for Omega-TipZ |
| 5469 |
Adapts mini banana plug (DAM80) to 0.031-inch receptacle (metal microelectrode) |
| 5470 |
0.031-inch jack, 28 ga. wire, 12 inch (pkg of 4) |
| 5482 |
Pins, 0.031-inch, gold-plated (pkg of 50) |
| 5483 |
Sockets, 0.031-inch gold-plated (pkg of 50) |
|
