[Boatanchors] 0Z4 Rectifier

[Jim Haynes]

I've wondered from time to time why the 0Z4 rectifier was used in,
and used only in, automotive radios with vibrator power supplies.

And what renewed the question is that I just bought on ebay a Western
Union power supply that runs off the AC power line rather than a
vibrator, and uses a pair of 0Z4 tubes.  The name plate is hard to
read but seems to say the output is 17.5-20.5 volts at 0.500 amp.
That seems like both too-low a voltage and too high a current for
0Z4s.  I haven't opened it up yet nor applied power to it.