The electrical characteristics of electroconductive gels used in biomedical applications

Electroconductive gels are widely used in biomedical applications for a proper transmission of produced signals to related body points of patients. During the transmission the biomedical gels play vital role in terms of relatively small signal loss and hence effective treatment. In some cases, disposable electrodes with self-gel attachments are used for quick application, however there are several critical cases in which additional gel application is required such as electrocardiogram (ECG), electroencephalogram (EEG), Ultrasound, Transcutaneous Electrical Nerve Stimulation (TENS) and etc. The electrode gel and skin combination structure simulates a circuit equivalent which contains capacity and a series resistive. In this study the electrical characteristics of electroconductive gels are investigated based on this equivalent circuit. Five different commercially available electroconductive gels are used as dielectric material between copper plates constructed for simulating biomedical electrodes which operate as a capacitor. During the tests the capacitance and dissipation factors of the conductive gels are measured. Also conductivity and TDS (Total Dissolved Solids) values are obtained for gel samples. A comparison of these characteristics may facilitate proper gel choice in biomedical application.