the aip74hc/hct47 feature active-low outputs designed for driving common-anode leds or incandescent indicators directly. display patterns for bcd input counts above 9 are unique symbols to authenticate input conditions.
the aip74hc/hct47 incorporate automatic leading and/or trailing-edge zero-blanking control (rbi andrbo). lamp test (lt) of these types may be performed at any time when thebi/rbo node is at a high level. the aip74hc/hct47 contain an overriding blanking input (bi), which can be used to control the lamp intensity by pulsing or to inhibit the outputs.