Electrode lead wires

In more demanding applications, the electrode lead wires should be shielded, preferably by purchasing the type that has a fine coaxial braided copper wire around the central signal-carrying lead. The shield should be connected to the amplifier reference but not connected to the electrode signal wire itself since this would abrogate its shielding effect. 

The network of lead wires must provide optimum mechanical support to the pellets of active material that fill the void space. Sufficient conductivity has also to be provided by the grid. Grids for positive and negative electrodes are usually similar. In batteries designed for extended service life, the positive grid is made heavier to provide a corrosion reserve. For very thin electrodes, a lead foil is used as the substrate and current conductor. 

That is, to determine the correct corrosion rates in pitting corrosion, as shown in Fig. 37, it is necessary to know the local corrosion currents on the electrode surface. The corrosion current observed is, however, obtained as the total current, which is collected by the lead wire of the electrode. From the usual electrochemical measurement, we can thus determine only an average corrosion current (i.e., the corrosion rate). Hence if we can find some way to relate such an average rate to each local corrosion rate, the local corrosion state can be determined even with the usual electrochemical method. 

Figure 26. EXAFS spectroelectrochemical cell (A) front view, (B) top view, (C) side view, (D) assembly (a) auxiliary electrode compartment, (b) working electrode well, (c) reference electrode compartment, (d) X-ray window, (e) inlet port, (f) auxiliary electrode lead, (g) RVC working electrode, (h) Pt syringe needle inlet and electrical contact, (i) Pt wire auxiliary electrode, (j) Ag/AgCl(3M NaCl) reference electrode. (From Ref. 98, with permission.)...

The SCE is dipped into the analyte solution along with the indicator electrode. A voltmeter is then externally connected across the lead wires leading to the two electrodes, and the potential of the indicator electrode vs. that of the SCE is measured. 

The disposable micro-glucose sensor consisted of thin-film electrodes positioned on a glass substrate and a small sample chamber (the iimer volume of which weis only 20 nL) was brought into contact with a silicon chip. Measmements were possible with as little as 1 pL of sample. The sensor sUncture is depicted in Fig. 3.18.E. The 10 x 20 mm silicon chip had a V-shaped groove that was 100-pm in wide, 70-pm deep and 5-mm long, in addition to two square sample inlets and five contact holes to connect lead wires to electrodes, all of which were formed by anisotropically etching the silicon. Four working electrodes that were 200 pm in width, and one counter-electrode that was 1.5-mm wide, were formed on a Pyrex substrate. The silicon chip and the Pyrex substrate were thermally bonded. 

The reactions are carried out in a 200-mL tail-form beaker, with a tightly fitting rubber stopper through which the platinum electrode leads are inserted gas inlet and outlet tubes can be inserted as required. The cathode is a platinum wire carrying a 2 X 2 cm platinum sheet. The anode is a platinum wire onto which a shot of indium is beaten to form a 1 X 1 cm plate. The electrodes are placed 1-2 cm apart in the liquid phase, which is a mixture of organic solvents. 

Fig. 3.3. Pressure equalisation burette in a device for potentiometric titration. For full details of operation see original publication. A break-seal ampoule containing the titrating solution B which reacts with the contents of break-seal ampoules P in reactor R, C sintered filter, Z) 10 ml burette, E 2 mm capillary, F capillary tip, Pt wires from electrodes leading to potentiometer. T, T, 7 PTFE taps, 7J three-way glass vacuum tap.

This figure shows the conductor pattern 3 overlapping exposed parts of the electrode leads 13 and fanning out on the substrate 20 to form wider terminal areas for wire-bonding. Common connections 6 and 26 are provided. 

Fig. 6. Beaker type celL A Pyrex beaker B Alundum membrane C Side-arm contact to the mercury pool consisting of a piece of glass tubing through which is sealed a piece of platinum D Thermometer E Reference electrode F Cathode lead wire G Nitrogen inlet and outlet tubes (for removal of peroxides from anode compartment) H Glass or teflon covered magnetic bar / Magnetic stirrer. (Taken from Ref., p. 34)...

Figure 1. Principal circuit of high temperature cell for voltammetry investigations under excess gas pressure 1 - high-temperature stainless steel box 2 -quartz box 3 - crucible and country electrode 4 — indicated electrode 5 - reference electrode 6 - thermocouple 7 - Pt lead wire for crucible 8 - water cooling for cell cover 9 -valve of pressure release in cell 10 - hose coupling 11 - gas control valves 12 - intermediate gas container (filling volume -2 liters) 13 - gauge-pressure manometer.

Green lead connect to the working electrode (302SS wire loop). 

The cell consists of a small beaker with a top that will accommodate two electrodes as shown in Fig. 1. The cadmium electrode is made by plating cadmium onto a platinum wire that is sealed through the bottom of a small glass tube. The amalgam electrode is made by placing a small quantity of the cadmium amalgam in the cup of a special J-shaped glass tube with a platinum wire sealed into it. Electrical contacts are made by copper wires spot-welded to the platinum lead wires. 

The association of the DNP-Ab to the antigen-monolayer-functionalized electrode leads to the electrical insulation of the electrode support and to the introduction of an electron barrier at the electrode surface. Thus, in the presence of an electrically wired enzyme (e.g., ferrocene-tethered glucose oxidase), the bioelectrocatalytic current is inhibited upon the formation of... 

Four electrodes method was used to measure the surface D.C. conductivity of the samples. The electrical contacts between the leading wires and the pellet surface were made by gold sputtering decomposition followed by high purity gold paste addition. The... 

Figure 11.24. Apparatus used by Chiu (102) for parallel TG—DTG-DTA and ETA measurements. A. balance housing B, balance beam sheath C, beam stop D, quartz beam E, sample container F. thermocouple block G, sample measuring thermocouple H. ceramic tubing I, platinum jacket J. reference quartz tube K. sample quartz tube L, outer platinum electrode M, center platinum electrode N, cold beam member O. P. platinum lead wires Q, sample thermocouple junction R, reference thermocouple junction S. spacer T, ceramic insulation U, V. sample thermocouple wires W. platinum grounding wire.

The electrolysis is performed either m a platinum or an alumina cell, this being placed in a temperature-controlled furnace. Electrodes are usually either gold or platinum beads or plates soldered to the lead wires. A carbon anode can also be used ... 

Liquid membranes are prepared from immiscible, liquid ion exchangers, which are retained in a porous inert. solid support. As. shown schematically in Figure 23-8. a porous, hydrophobic (that is. water-repelling), plastic disk (typical dimensions 3 X 0.15 mm) holds the organic layer between the two aqueous solutions. For divalent cation determinations, the inner tube contains an aqueous standard soittt ion of MCI, where M is the cation whose activity is to be determined. This solution is also saturated with AgCI to lorm a Ag-AgCI reference electrode with the silver lead wire. 

A platinum dish serves as the electrolysis vessel and the cathode. It is placed on a water bath at 50°C. A 100-g. solid Ag bar with a welded-on Ag lead wire is used as the anode. The maximum current density of the cathode is 0.002 amp./cnaj The volt e drop across the electrodes is 1.4 v. A 6-v. battery is used as the power supply the current is 0.07-0.1 amp. 

M KCl) contains an Ag/AgCl reference electrode and an Ag/AgCl-Teflon sb with a self-assembled BLM at its end. In contrast to s-BLMs on metallic substrates where ion conduction is excluded, a sb-based BLM allows ion translocation across the lipid bilayer. The lead wires of the two electrodes shown in Fig. 1 are connected to the measuring instrumentation (see also Fig. 2). In this connection, it should be noted that the sb might be identified, respectively, as items 1 and 2, thereby eliminating one of the chambers... 

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