I've been making CS/EIS for a couple yrs  now  & have used the 9 V 
batteries & the "plug in the wall " type. I have,  --since I started,--  
wondered 
about the difference between using 3 nine V.  batteries & 4 nine V batteries ( 
& I know you wise guys it's 9 Vs  )  grin---but what would the benefit  be 
of using  3 batteries as  opposed to using 4.  ???????
   Now for my next "electrically challenged"  person question--- Would it 
be possible to use a cell phone battery  charger - or other "plug in the wall 
charger----cut the wire off the end  & hook up a multimeter & alligator 
clips to the silver wires to brew  CS/EIS   ?????  Lois
{{  I wish I knew more about electricity but ever  since lightening hit the 
straw stack & 6 of our milk cows were  smothered  & fired,,,& Mom got 
tossed across the kitchen by the  electric stove I have been  afraid of it...At 
least the house wiring   kind...}}