Pulse generators electrodes

Membrane charging through external resistances Coupling to the pulse generator, electrodes, and electrolyte (Figure 4)... 

Tyers GFO, Brownlee RR. Power pulse generators, electrodes, and longevity. Prog Cardiovasc Dis 1981 23 421-434. 

Ignition pulse generator including pulse generator with button, low tension cable, coil electrode and sight glass, if required. 

Electrodes are made using heavy duty foil affixed to both ends of a microscope slide with a small (5 mm) gap in between. Wire loops are sandwiched between layers of each foil electrode. The wire loops can then be connected to the pulse generator. 

Figure 18.4 Pulse generator and applicator electrode for in vivo electroporation. The applicator electrode shown here consists of six needles and is used for intra-tumoral and intra-muscular applications in large animals. Two needle applicator electrodes for use in rodent muscles are commercially available.

An interesting extension of the cpe technique is pulse electrolysis. The electrode is maintained not at one single potential, but at a series of potentials of controlled duration according to a predetermined program. Tills is done by means of a pulse generator (also commercially available). Pulse techniques have hitherto been used mainly for mechanistic studies 91,92-1 but hold great promise for synthetic applications too 90,2 65 As an example, in the anodic oxidation of aliphatic hydrocarbons in non-aqueous medium at a platinum anode, the electrode activity falls rapidly with time if the potential is kept constant, probably because of the formation of an adsorbed film of intermediates or products. However, regular, short cathodic pulses reactivate the anode and the reaction proceeds without difficulties 30 ... 

There is another important diffusion problem, the solution of which can be generated from the concentration response to a constant current (or a flux). Consider that in an eleetroehemieal system there is a plane electrode at the boundary of the eleetrolyte. Now, suppose that with the aid of an electronic pulse generator, an extremely short time eurrent pulse is sent through the system (Fig. 4.28). The current is direeted so as to dissolve the metal of the eleetrode hence, the effect of the pulse is to produee a burst of metal dissolution in whieh a layer of metal ions is piled up at the interface (Fig. 4.29). 

Fig. 4.28. The use of an electronic pulse generator to send an extremely short time current pulse through an electrochemical system so that there is dissolution at one electrode during the pulse.

Figure 4 Sketch of the electrochemical STM for short-pulse surface modifications. The potential of the working electrode (WE) is controlled by a low-frequency potentiostat (Pot) versus the reference electrode (RE) via the counterelectrode (CE). The tunneling voltage (Ut) is supplied via the I/U converter of the STM (A) and a low-pass filter (LP). To apply the short pulses to the STM tip, a high-frequency pulse generator (Pulse) is switched onto the tip for a few milliseconds.

A practical system used to stimulate a nerve consists of three components (i) a pulse generator to generate a train of pulses capable of depolarizing the nerve, (2) a lead wire, the function of which is to deliver the pulses to the stimulation site, and (3) an electrode, which delivers the stimulation pulses to the excitable tissue in a safe and efficient manner. 

The term implantable stimulation refers to stimulation systems in which all three components, pulse generator, lead wires, and electrodes, are permanently surgically implanted into the body and the skin is solidly closed after the implantation procedure. Any interaction between the implantable part and the outside world is performed using telemetry principles in a contact-less fashion. This chapter is focused on implantable neuromuscular stimulators, which will be discussed in more detail. 

Implantable stimulation systems use an encapsulated pulse generator that is surgically implanted and has subcutaneous leads that terminate at electrodes on or near the desired nerves. In low power consumption applications such as the cardiac pacemaker, a primary battery power source is included in the pulse generator case. When the battery is close to depletion, the pulse generator has to be surgically... 

Cerebellar stimulation—Among the earliest stimulators from this category are cerebellar stimulators for control of reduction of effects of cerebral palsy in children. Electrodes are placed on the cerebellar surface with the leads penetrating cranium and dura. The pulse generator is located subcutaneously in the chest area and produces intermittent stimulation bursts. There are about 600 patients using these devices (Davis, 1997). 

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