 The Sovereign used a <unk> <unk> main integrated circuit , the same as the Sinclair <unk> <unk> and some variants of the Sinclair Cambridge . Clive Sinclair had assumed that people would prefer attractive illuminated LED displays to <unk> displays , which incidentally also required more expensive <unk> chips . However , his calculators were designed with the assumption they would be turned off between calculations , which did not prove to be the case . Advertisements suggested that the batteries would last " about a year " under normal use , but in reality the small button cell batteries and comparatively high power consumption meant a short battery life compared to the competition . 
