> where would my friend get 10 volts from?

A couple of MC34063 would provide +/- 10V from a single
DC supply

eg here's -10V I need for an LCD

http://home.clear.net.nz/pages/joecolquitt/bmp2lcd.html

with another MC34063 as a positive step-down/up, depending
on the DC supply value

As Isaac said, a 78xx can be used for the +10V. It needn't
necessarily be a 7810, as the reference ('ground') pin can be
lifted above 0V. Similarly an LM317

Joe
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