Miniature calculator having push-button on-off switch

摘要: A miniature calculator is provided with a keyboard having small opening which has recessed operating switch may be pressed by the user. The so that accidental operation of difficult. When turned on and button pressed, will turn off. off, depressed for less than 2 seconds, on. If off longer after two second delay, since this an apparent depression. logic circuit controls connection regulated power supply to circuitry in accordance condition push keyboard. current contains eliminates ''''low end'''' problem wherein output voltage even substantial decrease battery voltage. also display time-out such numerals flash at relatively short duty cycle of, example, percent, been given time order conserve power. low cause flashing dot display.