OUTPUT VOLTAGE (V) AND CURRENT (A). Application requirements for supply voltage vary widely. To accommodate these needs, medical power supplies offer either single or multiple output voltages, typically in the range of 3.3 to 48 Vdc. When determining the supply-voltage levels required in an application, note the current levels that will be required at each voltage. POWER RATING (W) If only a single supply voltage is needed, the power rating required of the supply will simply be the supply voltage times the maximum current required in the application. If multiple outputs are needed, add up the voltage-times-current products for all of the supply voltages to determine the power rating. Good engineering practice dictates that you select a power supply model with a rating that provides some design margin. FORM FACTOR AND MOUNTING Medical grade supplies are offered in a variety of package styles including open- frame, enclosed, encapsulated, and external adapter with a range of mounting options such as PCB mount and chassis mount. The selection of a particular package style depends on a number of application considerations. The advantages of the various package types are described in the other sections of this source book. ELECTRICAL CONNECTION The options for power supply input and output connections (I/Os) are related to the choice of mounting options. With pc-board mount packaging, I/O pins on the bottom of the supply insert into plated-through holes or sockets on an application pc board. With chassis-mount packaging, the supply may include Molex headers or screw terminals that enable interconnects to be made using wire harness assemblies. THERMAL MANAGEMENT The ambient temperature range expected in the application together with power supply thermal specifications will determine whether convection cooling is sufficient or if forced-air cooling may be required. Note that the packaging style will affect thermal performance and cooling requirements as outlined in the other sec- tions of this source book. ENVIRONMENTAL FACTORS For applications where the power supply may be exposed to vibration or contaminants, power supply reliability can be enhanced by the selection of an encapsulated power supply. See the “Encapsulated Power Supplies” section for more on this topic. SAFETY STANDARDS Medical-grade power supplies must meet the IEC60601-1 safety standard for medical electrical equipment as implemented in regional versions such as UL60601-1 and EN60601-1. These standards impose additional safety requirements (relating to creepage and clearance spacing, isolation voltage and leakage current) beyond the requirements of the general safety standards UL/EN60950-1. Medical-grade supplies also must meet these general standards. With regard to leakage, UL60601-1 specifies a limit of 0.3 mA of leakage current from input to output for Class I equipment. Within a power supply, most of the leakage is caused by the EMC filter on the input. However, equipment designers should be aware that other components in the system can contribute additional leakage. PATIENT CONNECT VS. PATIENT VICINITY According to UL60601-1, electrical equipment is classified as “patient vicinity” if it is intended to be located within 6 feet of a patient. If electrical equipment is intended to come into direct contact with a patient, it is classified as “patient connect” and requires an additional level of isolation. Medical-grade power supplies are typically certified under the patient vicinity requirements since they do not come into direct contact with patients. ADDITIONAL HORIZONTAL STANDARDS In addition to meeting the IEC60601-1 standard, applications may also demand compliance with collateral medical equipment standards such as IEC60601-1-2, which defines requirements for electromagnetic compatibility. There are numerous other collateral standards relating to other hazards and specific medical applications. Determine which standards apply in your application and whether they affect power supply selection. DUAL LINE FUSING UL/EN60601-1 requires fusing on both the line and neutral wires in equipment with a protective earth ground. This fusing can be accomplished in the power supply or externally in the system http://www.astrodynetdi.com/about/blog/astrodyne-blog/2016/01/29/medical-grade-power-supplies-ten-important-criteria
If 99% of humans are dead, that leaves 70 million alive; that's more than the population of the UK, more even than the population of any endangered species by a factor of several. If 99% of humans are dead, that leaves over a thousand in my small town...Quite enough diversity to avoid inbreeding. Generally, incest laws in the Western world prohibit breeding with a 25% coefficient of relationship... https://en.wikipedia.org/wiki/Coefficient_of_relationship and this is sufficient to avoid significant inbreeding issues, even if you marry your cousin...(the Habsburg lip was the result of 6 centuries of "maintaining a pure blood line" - not just "a couple of generations")...and this could be satisfied within a very small population, probably less than 100.
I think inbreeding would be the least of the problems for the surviving population. However let's say that whatever caused the sudden zombie invasion also sterilized the population or made all newly naturally conceived babies have the "zombie virus" in their system, there might be some angle for the OP to work for the story line that was suggested.