reset

set title "Eingangswiderstand des Oszilloskops"
set xlabel "[t in s]"
set ylabel "[R in Ohm]"
set grid xtics ytics
set key top left

t1 = 0
U1 = 55.2
C = 0.47e-6

f(x) = m * x + a
fit f(x) 'DatenEntladung.txt' us ($1)-0.400:(($1)-t1-0.400)/(C*(log(U1) - log($2))) via m,a

plot \
'DatenEntladung.txt' us ($1)-0.400:(($1)-t1-0.400)/(C*(log(U1) - log($2))) notitle lt 1, \
f(x) title "Ausgleichsgerade" lt 3

set output "entladung.eps"
set term postscript enhanced eps color; replot