1 Feb
2011
1 Feb
'11
1:16 p.m.
On 1 Feb 2011 at 19:03, Tony Duell wrote:
I think the voltage will depend on various things. I've heard it
quoted as 117V/234V [1] but that was some time ago, so it may well
have changed...
It's been variously quoted as 110/220, 115/230, 117/234 and today,
120/240. The "standard" has crept up over the years. Japan, I
believe, is still 100V, although it can be either 50 or 60 Hz.
I was under the impression that the US mains was in
fact 220V (or
230V, 234V, depending on which reference you believe),
centre-tapped. The centre-tap is the 'neutral' wire and is
connected to earth ground at one point. The outside 2 ieres are
this 110V with respect to neutral, but as they're in antipahse
there's 220V between them.
Yes, I think that's the basic setup, but as Chuck noted the voltage
of one half is around 120V, not 110V (I got 122.8V on a nearby
outlet just now) [1] Anyone else remember valves like the 117Z which
was (IIRC) a
double diode recrtifier with a 117V (!) filament. I think there wsa a
half-wave rectifer/ooutput pentode with a 117V filament too, used in
cheap record players.
117L7/M7GT if memory serves. Another combination was a 70L7 beam
power tube with a 35Z5 rectifier and a 12SK7 (or other 12.6V pentode
or triode).
Weren't there also some European countries (or parts thereof) that
used various DC voltages for lighting and small appliances? (Belgium
or Italy?).
Another artifact of earlier days in US industrial applications is
55/110/220/440V 25 Hz distribution. The power transformers are huge
and the "hum" is more of a "rattle".
--Chuck