symmetric dimming circuit for transformer.

[tcmtech]

So what's wrong with just using a Variac transformer and turning the whole AC voltage up and down?

Thats how I have made variable AC power supplies for years. Cheap, rugged, reliable, and simple.

 

[MrAl]

So what's wrong with just using a Variac transformer and turning the whole AC voltage up and down?

Thats how I have made variable AC power supplies for years. Cheap, rugged, reliable, and simple.

Hi,

Did you say "cheap" ?

 

[tcmtech]

Sorry I forget that not everyone has boxes of these sort of devices laying around from scrapping work. Cheap for me.

However that said a good used 100 VA variac can usually be had for around $25. Given that it would be running in an autotransformer type application he wouldn't need a very big one to drive his 150 VA transformer.

 

[dr pepper]

All done and cost nowt.
A variac is something I dont have, not scrapped anyhting that old.
My mig welder uses a variac to control the wirefeed motor, but thats staying put.