How do relays work?

["Watry, Andrew" <Andrew.Watry@domain.elided>]

Relays are prescribed as the fix for a number of electrical ills, especially
where there seems to be a voltage drop over a long distance.   Along with
helping out Spica pump solenoids and the like, I just read that relays were
a standard fix in the 60s for weak headlights on 6-volt VWs and Porsche
356s.  How do relays work?  Seems to me like getting something for nothing
or pulling yourself up by your bootstraps. How do you get better voltage
going out than coming in?

Andrew Watry

------------------------------