When answering the questions below, you may assume that the source resistance is negligible and that each diode has a potential difference of 0.6 V across it when conducting. For the circuit below calculate (a) the current in the 30 Ω resistor, (b) the current in the 60 Ω resistor, (c) the PD across the 40 Ω resistor.
Answers: (a) zero, (b) 0.054 A, (c) 2.16 V
2. The attempt at a solution
(c) 1/R = 1/30 + 1/40 → R = 20 Ω → total R = 20 + 40 = 60 Ω. I = V / R = 6 / 60 = 0.1 A. V40 = I R40 = 0.1 * 40 = 4 V.
(a) VParallel = 6 - 4 = 2 V. I30 = VParallel / R30 = 2 / 30 = 0.067 A.
(b) V = 2 / 60 = 0.033 A.
Doesn't fit the answer. I looked at the theory behind the diods. Still don't understand why the current in the 30 Ohm resistor is zero.
Is it because current goes from the cathode part and therefore it is zero? Or because there are two diods and therefore the second one should have a current of zero?