Yes, I have only one coil. Transformer has only one secondary whcih is giviing me 19V AC . I can not change the transfomer . Already +24V is generated through rectification.
regulation is not necessary. Little variationis accepted on -24V line .
How to generate -24V @ 0.25A either by 19V Ac or +24V dc output ?
Or you could just use half wave rectification like I suggested a few days ago. I don't see what the purpose of a voltage doubler is when you actually request a negative and positive supply.