Due to the presence of two simultaneous processes observed with EIS during the HER, the EC with which to model p-Si|a-TiO2|Pt devices was previously ambiguous. This ambiguity had implications on the mechanism of charge transfer through these devices, and therefore was important to resolve. This was achieved by substitution of the a-TiO2 protection layer with both SiOx and c-TiO2, which resulted in unambiguous resistance and capacitance values for the silicon substrate during the HER. Taking the silicon resistance found using EIS to be equivalent to the dc resistance, it was confirmed that the Maxwell circuit is the appropriate EC with which to model a-TiO2 protected devices during the HER.