1445326735900-0

Starting electronics
Figure 11.14 The function table of the clocked, edge-triggered, SR-type bistable
of Figure 11.13
Such an approach of simplifying circuits is very common in
electronics, and we’ve come across it before — the black-box
approach. The approach relies on the fact that we don’t need
to know how a complex circuit is constructed — we only need
to know its function.
Every single one of the other logic gate types we’ve seen
in this chapter can also be represented in black box block
form by symbols, and to prove it, we’ll consider them all
now. All you have to do is remember that if necessary they
can — and sometimes are — built using logic gates, but you
don’t need to know how to construct them that way because
— yes, you’ve guessed it — they can be bought ready-built
in IC form, in the same series (7400 and 4000) we’ve already
used and are familar with.
First is the D-type bistable. Its circuit symbol is shown in
Figure 11.15, while its corresponding function table is in
Figure 11.16.
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