need slight DC voltage reduction, 1 volt signal

[evotec1]

yeah so basically i need a circuit that when 1 volt is fed in,  .9 volts goes out.  The ability to adjust the output from 1 volt to say .8 would be great.

Heres what i tried

1v source--- --------- -------------------------------------------------destination----------G
                                |
                                |
                                |
                                Z = 1 megaohm pot
                                |
                                |
                                G

And

1v source-------------------------NN------------------------------destination----------------G
                                                /\
                                                |
                                                |
                                  here i have tried a 10k trim pot and the megaohm pot

WHAT DO I DO?????

I understand that adding just resistance to the line probably just made it draw more current, but i dont understand the voltage divider circuit in my friends old basic electronics book either.  Will adding another resistor to the top diagram make it work?

[Omni]

What voltage is required at the output to power the device?