... follows, the positive logic convention will be used Any voltage between ground (Gnd) and +0.8 V represents a logic A voltage between +2.4 V and +5.0 V (Vcc) represents a logic A voltage between ... arbitrarily selected and required to generate a logic 1, then the upper AND gate must generate a logic 1, requiring that inputs X1 and X2 must both be at logic As before, a known value must be assigned ... R1, D1, and D2 If either X1 or X2 is at logic 0, then the base of Q1 is at ground potential; hence Q1 acts like an open switch Likewise, if Y1 or Y2 is at logic 0, then Q2 acts like an open switch...