[Amps] AC filament voltage regulator

[John G3UUT]

I've also been thinking about this problem and the reason I'm not keen 
on a DC regulator is that the distortion and peak current of the mains 
current waveform is already pretty bad with a capacitor input B+ supply 
and making it worse by adding the heater as well will undoubtedly make 
the regulation of the B+ worse.  This is particularly a problem when 
using portable generators.

I've not taken this down to circuit level yet but my idea was to use one 
of the Analog Devices RMS to DC convertors as its important to maintain 
the RMS of the AC constant - especially when using poor quality mains 
from a generator.  Hsu - this is the problem with your circuit.  My 
other idea was to use a biphase rectifier with a centre taped 
transformer and schottky rectifiers to reduce the diode losses - which 
are quite significant with a 5 V heater.

73 John G3UUT

On 10/07/2011 03:03, Dr. David Kirkby wrote:
> On 07/10/11 01:12 AM, Hsu wrote:
>> I do not think a DC regulator  for direct heater tube is a good idea,I draw  a block diagram for AC filament regulator here:http://www.zmdz.com/bbs/incomefiles/20117/1089098780.JPG, just a block diagram.any advice? I know we have another selection,CVT. a special transformet.
>>      73!Hsu
> What's wrong with a DC regulator?
>