[AMPS] Filament voltage inrush

[Steve Thompson]

In message <199902050306.WAA69326@pimout3-int.prodigy.net>, frank ayers
jr <LOMAX1@prodigy.net> writes
>
>There has been a bit of discussion recently about resistors in series with
>the primary of fil xfrmrs. What about the use of the thermistor gizmos? As
>I understand it, they start out around 50 ohms then drop down as they heat
>up. Anybody have any idea how well these would work for inrush protection?
>
>
>Frank
>W2FCA
If you are using a primary side resistor to control the load voltage, it
needs to be a stable, fixed value (assuming your incoming line is stable
voltage). The inrush thermistors do a great job on inrush - I've added
them to a number of bench supplies here and the lights don't flicker
anymore. I wouldn't recommend them on a supply where the output isn't
stabilised - they are likely to mess up the output regulation.

Steve

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