Pulse generators battery

Similarly to electric primers, (described in Section 4, Part E), these electric detonators may be made to fire from suitable sources of electrical energy, such as generators, batteries or charged condensers they may thus be made to fire from an electric pulse supplied by energy stored within fuze firing circuit or by an electric pulse generated within the fuze system prior to or at impact... 

The longevity of very early pulse generators was measured in hours, but current devices can function for more than a decade before they need to be replaced due to battery depletion. The chnical desire to have a generator that is small and full featured, yet also long-lasting, poses a formidable challenge to battery designers. 

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... 

A cardiac pulse generator is a device having a power source and electronic circuitry that produce output stimuli. Functionally, at its simplest, current sourced by the device s battery travels through a connecting pathway to stimulate the heart and then flows back into the pacemaker to complete the circuit. 

Fig. 2.1 At beginning-of-life (BOL), the lithium iodide battery exhibits an output voltage of 2.8 V, which slowly decays until it nearly depletes, whereupon the voltage decays more rapidly. At around 2.0-2.4V, the elective replacement indicator is triggered, which usually leaves 6 months before the pulse generator will begin to behave abnormally as it reaches its end of useful life (EOL).

Fig. 2.14 (a). Status screen and modern pulse generator capable of storing sequential measurements of lead impedance and displaying the trend graphically, (b). Interrogator screen shows battery status in an easily understandable pattern. 

Passive fixation leads are available that provide a high lead impedance, thereby minimizing current used for pacing and battery drain (31). This is an attractive concept, considering the fact that the typical pediatric patient will need many pulse generator changes during their lifetime. 

All pulse generators can be identified radiographically to some degree. Historically, the position of the cell or battery and the position of the radiopaque circuit components were unique to each model. However, as the shape of pulse generators has become less distinctive, identification of the manufacturer from these characteristics alone is not usually possible. Most pacemakers have an identification code visible on radiographic views of the generator. Once the radiographic code and manufacturer have been identified, the company can be contacted via a toll-free telephone number and the company s technical service staff should be able to assist in pacemaker identification. 

If a portable AM/FM radio receiver is available, place it about three feet from the inductor and battery. (If a small radio is not available, the inductor and battery can be taken outside, near an automobile radio.) Turn on the radio, set it for AM, and tune the frequency dial to a number where there are no nearby radio stations, so only a very low level of background noise is audible. Turn the volume up somewhat. Disconnect the neon tester, and then make repeated sparks with just the inductor and battery, as shown in Fig. 1.2, but using the primary coil (heavily insulated black wires). Loud clicks will be heard from the radio loudspeaker, each time a spark is made. The high voltage pulse generates a radio wave, which travels through the air to the radio antenna. (Further analysis of these various aspects of radio theory will be explained in later chapters.)... 

When the lead is in proper position, the surgeon secures the pulse generator in a subcutaneous pocket of tissue just below the patient s clavicle. Changing the generator s battery or microchip circuitry requires only a shallow incision over the site and a quick exchange of components. 

If pulse generator is on but indicators aren t flashing, change battery. If that doesn t help, change pulse generator. 

If the pacemaker isn t functioning correctly, change the battery or pulse generator. 

Space occupied by the battery in the pulse generator unit 5—8 cm. ... 

Fig. 11 The actuarial survival curves for an implantable pulse generator. The lower curve shows the pulse generator s survival as a function of batteiy depletion. Battery depletion is a normal and expected outcome so this is not considered a device failure per se. The upper curve depicts what the pulse generator s survival statistics would be if the battery s longevity were not taken into account. Thus the upper curve measures the reliability of the circuitry, hetmeticity, feed throughs, etc.

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