Decoder
Decoder: whatever number the n-bit input A holds, that output Y goes to 1 and the rest stay 0 (one-hot).
Function table (2-bit example)
| A1 | A0 | Y0 | Y1 | Y2 | Y3 |
|---|---|---|---|---|---|
| 0 | 0 | 1 | 0 | 0 | 0 |
| 0 | 1 | 0 | 1 | 0 | 0 |
| 1 | 0 | 0 | 0 | 1 | 0 |
| 1 | 1 | 0 | 0 | 0 | 1 |
Pins
Inputs A on the left (higher number = higher bit), outputs Y0, Y1… on the right. Use + / − to change the number of input bits.
How to use it
Address decoding and chip select. Each Yₖ is exactly one minterm, so one OR gate on top gives you any function.
Usage example
The two-bit input A1 A0 goes on the left and each output drives an LED. With A1 A0 = 10 (that's 2), only Y2 lights.