Question

The characteristic equation of S-R latch is ____________

(a) Q(n+1) = (S + Q(n))R’

(b) Q(n+1) = SR + Q(n)R

(c) Q(n+1) = S’R + Q(n)R

(d) Q(n+1) = S’R + Q'(n)R

The question was posed to me during an internship interview.

The query is from Flip Flops topic in portion Flip-Flops of Digital Circuits

Answer 1

Right option is (a) Q(n+1) = (S + Q(n))R’

The explanation is: A characteristic equation is needed when a specific gate requires a specific output in order to satisfy the truth table. The characteristic equation of S-R latch is Q(n+1) = (S + Q(n))R’.