Abstract: Accumulating measuring devices which indicate the flow of electric current on graduated scale. Current flow may be of any fixed rate or value, steady or pulse, and scale may be any desired graduations. Current flow is indicated by a persistent electrochromic display material which changes color due to passage of electric current through it. The entire device is electronic, with no mechanical parts. Other accumulating functions may also be measured with the device if they can be converted first to electric current. One particular application is an elapsed time indicator, e.g. a watch or clock.