(a) (b) (c) Figure $16

Question

(a) (b) (c) Figure $16 < 1$ -What is the current through R₁ in Figure 16-1(c) if the diode is silicon?

Quizplus · Accepted Answer

Assuming the diode is in forward bias, we can find the voltage drop across it by subtracting the voltage at node RS1U1B11S1 from the voltage at node S1U1B0.

Vdiode = VS1U1B0 - VRS1U1B11S1 = 2.5 V - 0.7 V = 1.8 V

Using Ohm's Law, we can then find the current through RS1U1B11S1U1B0:

I = V / R = 1.8 V / 36.3 ohms = 0.0496 A = 49.6 mA

However, the question asks for the current through RS1U1B11S1U1B0 if the diode is silicon, which means that it has a 0.7 V threshold voltage before it begins conducting. In this case, the voltage drop across RS1U1B11S1 is only 1.8 V - 0.7 V = 1.1 V.

Using Ohm's Law again:

I = V / R = 1.1 V / 22.5 ohms = 0.0489 A = 49.3 mA

Thus, the answer is (B).

(A) (B) (C) Figure 16<116 < 116<1

(A)

(B)

(C)

Figure $16 < 1$