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Old 29th Dec 2018, 11:20 am   #6
Cathode Ray
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Join Date: Dec 2018
Location: County Meath, Ireland
Posts: 242
Default Re: Variac first or Isolation first ?

Quote:
Originally Posted by Refugee View Post
They do make the lights flicker some times at switch on.
This may explain why its only 'sometimes' ...
https://electronics.stackexchange.co...use-at-no-load

It depends on where in the cycle the power is applied.

A correctly rated NTC Thermistor or soft-start circuit should sort it out.

See diagram, this is a soft-start circuit from an Ameritron HF amp.
D1, R3 and C3 delay the closing of K2, allowing R4 and R5 to limit the surge for a few cycles.

Ray
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