what is (sheet resistance) ?

[loveinharovrd]

r = ρ * l/a

R=ρL/A where A=H*W H=hight W=width
R=ρL/H*W
1.R=ρ*(L/A)=(ρ/H)*(L/W) where Rs=(ρ/H) sheet resistance ->R=Rs*(L/W)
2.R=ρ*(L/A)=(ρ/A)*L where Rs=(ρ/A) sheet resistance ->R=Rs*(L/W)

which is correct ??

 

[Kral]

loveinharovd,
1) R = Rs[L/W]
2) R = p[L/A]
3) R = p[L/(H*W)]
Set 1) = 3):
3) RsL/W = pL/(H*W)
4) Rs = p/H
This is true if you define L to be parallel to the direction of current flow during the measurement.
Regards,
Kral