[Amps] Switching Power Supplies

[Will Matney]

See Below;

*********** REPLY SEPARATOR  ***********

On 7/15/06 at 12:00 AM Ian White GM3SEK wrote:

>Tony King - W4ZT wrote:
>>
>>The reason I chose a small switcher for my filament supply was to 
>>provide a stable DC filament voltage over changing input line voltages.
>
>In Field Day use, with more than one station hooked up to the same 
>generator, there can be violent swings in the line voltage as stations 
>switch unpredictably between transmit and receive. A regulated 
>filament/heater supply could prevent damage due to insufficient cathode 
>temperature.

I tee-totally agree. I would want the heater supply to be DC, and be regulated. Any fluctuations then
will not affect the heater voltage. Running DC on a heater will also increase heater life. It's the same 
as using a rectifier on a standard lamp in the home. The life would be a good bit increased I would
think where the current wouldn't be alternating.


>
>I'd certainly consider a switcher for that application. There is no 
>shortage of well-designed, well-shielded switchmode supplies with good 
>input and output filtering.


One can rectify the line voltage then step up the frequency in a transformer-converter circuit and get
the same results. The square wave output can then be rectified, filtered, and regulated. The transformer
will be a good bit smaller in size. I would run one anywhere from 400 Hz to 1 kHz.That would make
for a good light weight amp. If it's filtered well, I don't think the heater or cathode would be effected as
far as interference.


>
>
>
>-- 
>73 from Ian GM3SEK
>
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Best,

Will