The way this component work is more simple that you may think.
At start, the component look for the 4 bits binary value set on the input pins (so between 0 to 15, with 3 bits we can still encode from 0 to 7).
Next, from this decimal value decoded between 0 to 9, the component activates the corresponding output numbered from 0 to 9 (the output is set HIGH while the other outputs are LOW).
In retro computer, this component is used to selects/activates a given device based on 3 bits of a base address (eg: from 0xFFFAA0x to 0xFFFAA9x)
- 3 to 18V
- Input: 3 to 4 bits
- Output: 8 to 10 output I/O (octal-decimal)
- Logic Circuit
- DIP 16
- CD4028BE Datasheet (pdf)