The series resistance of a planar Schottky barrier diode fabricated on ptype silicon is investigated by analysing the current-voltage characteristics of the device. Different characterisation techniques have been applied to obtain the value of the series resistance of the device. It is found that the existing techniques are either not applicable for the present device or yield unreliable value for the series resistance. A numerical analysis of the I-V data reveals unusual voltage dependence of the series resistance of the device. The anomaly has been resolved by postulating a potential barrier at the ohmic contact and drawing analogy to serially connected high and lowbarrier diodes in a backtoback configuration. It is found that the voltage dependence of the series resistance of the device can be described by certain empirical law, which also applies to device on GaN. The measured voltage behaviour of the ac resistance and capacitance of the device at different frequencies have been found to be consistent with those of a serial combination of diodes considered to verify the postulate made in interpreting the I-V data. © 2012 Copyright Taylor and Francis Group, LLC.