A simple device for the reliable production of varnish-insulated, high-impedance tungsten microelectrodes

The construction and operation of a simple device that produces varnish-insulated, high-impedance tungsten microelectrodes for single-unit recording is described. In essence, the device operates as a high-voltage pulse generator whose output creates an arc between a fully insulated tungsten microelectrode and a polished counter-electrode. As a result, insulation is removed reliably and symmetrically from the microelectrode tip. The device is constructed with a minimal outlay of time, skill, and money.