This post explains for the TTL 7447.
The Part Number is 7447.
The function of this semiconductor is BCD to 7-Segment Decoders/Drivers.
Manufacturers : Fairchild Semiconductor
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DM7446A, DM7447A BCD to 7-Segment Decoders/Drivers
General Description The DM7446A and DM7447A feature active-LOW outputs designed for driving common-anode LEDs or incandescent indicators directly. All of the circuits have full ripple-blanking input/output controls and a lamp test input. Segment identification and resultant displays are shown on a following page. Display patterns for BCD input counts above nine are unique symbols to authenticate input conditions. All of the circuits incorporate automatic leading and/or trailing-edge, zero-blanking control (RBI and RBO). Lamp test (LT) of these devices may be performed at any time when the BI/RBO node is at a HIGH logic level. All types contain an overriding blanking input (BI) which can be used to control the lamp intensity (by pulsing) or to inhibit the outputs. Features s All circuit types feature lamp intensity modulation capability s Open-collec […]