Now if a is in the C1 register and if c is in the C5 register, then negation will be:
| C1 | C5 |
| 00 | 00 |
| 01 | 11 |
| 10 | 10 |
| 11 | 01 |
But each of these registers C1, C5 will be made up of two relays, the left-hand or 2 relay and the right-hand or 1 relay. So, in terms of these relays, negation will be:
| C1-2 | C1-1 | C5-2 | C5-1 |
| 0 | 0 | 0 | 0 |
| 0 | 1 | 1 | 1 |
| 1 | 0 | 1 | 0 |
| 1 | 1 | 0 | 1 |
Now, on examining the table, we see that the C5-1 relay is energized if and only if the C1-1 relay is energized. So, in order to energize the C5-1 relay, all we have to do is transfer the information from C1-1 to C5-1. This we can do by the circuit shown in [Fig. 6]. (In this and later diagrams, we have taken one more step in streamlining the drawing of relay contacts: the contacts are drawn, but the coils that energize them are represented only by their names.)
Fig. 6. Negation—
right-hand digit.
Fig. 7. Negation—
left-hand digit.
Taking another look at the table, we see also that the C5-2 relay must be energized if and only if: