Jon Elson wrote:


I remember renting a student apartment in Boston circa 1955 and
finding out to my horror that the place was still on DC.

I was a "Hi-Fi" buff at the time and couldn't put up without AC to run
all my gear, and I didn't want to try and get by with the vibrator DC
to AC inverters available back then.

So, I moved out the day after I moved in, and the landlord was nice
about it.

My God, what COULD you run off DC back then?

Light bulbs fer sure. G

Let's see, most vacuum
cleaners had universal motors and would probably run on DC, I guess
smaller TVs and table radios would run on DC, but that might be about
it!


Many small radios back then were referred to by the cognizanti as "AC/DC
Sets". They had no power transformers in them and they used tubes with
various filament voltages like 12, 35 and 50. The typical 5 tube set
would run all the tube filaments in series from 120 volts (AC or DC, it
didn't matter which.) I can't recall whether the line cord was polarity
sensitive and had to be plugged in the "right way" to get electrons to
flow through the rectifier tube (usually a 35Z5 ?). Perhaps some antique
radio buff will check in here on that.

But, I don't recall ever seeing a TV which would work off DC line voltage.

OK, toasters and mixmasters would probably work, too. Window fans,
electric clocks, and all sorts of other stuff would not, and some of it
would be pretty catastrophic! As for Hi-Fi gear, you'd be stuck with a
hand-crank Victrola! I guess people were more aware of this stuff back
in '55 than today, but I would suspect a LOT of folks would balk at DC
only even back then. A lot of places had multiple supplies, both DC AND
AC back then, as not all appliances could handle AC, in areas that had a
long Edison history. Then, you just had to be careful what you plugged
into where.

Jon

Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10e12 furlongs per fortnight.