Patent ID: 8299797

Claim:
An apparatus for evaluating an earth formation penetrated by a borehole, comprising: a plurality of azimuthally spaced-apart pads each having at least one electrode thereon and configured to be positioned proximal to a wall of said borehole; operational circuitry adapted to operate a first one of said electrodes as a first transmitter electrode and at least a second electrode, on a different pad than said first electrode, as a first return electrode, such that current is driven along a first current path between said first transmitter electrode and said first return electrode, resulting in a first measurement signal being detectable at said first return electrode; processing circuitry for determining a first property of said earth formation based at least in part on said current on said first current path and said first measurement signal; wherein one electrode on each one of said plurality of pads is separately selected, in a predetermined sequence of said pads, to transmit current conducted from the selected pad to at least one other one of said plurality of pads.