DIY Mains Regulation - Oops, I forgot to factor in heat dissipation

[Paul Birkeland]

Last question for the day (I promise!): in your diagram the series connection of the bucking secondary to the AT is made at the end of the AT winding. In my case, this would correspond to the 125 VAC tap, which I didn't plan on using. My plan was to connect the mains to 105, 110 or 115 VAC (switchable) and take the output from the 115 VAC. So I should connect the bucking secondary at the 115 VAC tap, right?

Since you are intending to go up, then yes, I would have the buck/boost transformer connected at the 115V connection.  You could wire up a switch to go up or down 2.5V, though just having a booster winding will give you what you need IMO. 

 

[Deke609]

Many thanks PB. Yes, I'm thinking of putting the connection to the buck/boost on a switch (on/off), which in turn will throw the "on" selection to a second switch for choosing between in-phase +2.5V or out-of-phase -2.5V. Which is actually a lot more useful than my imagined diode trimmers, which would have only dropped voltage.

Many thanks to you, PJ and John for helping me with this. This new approach is even better than what I had hoped to achieve with my original plan.

cheers, Derek