The diode in the shown circuit has a constant forward drop 0.5 V and maximum power rating 100 mW. Find the series resistance R in Ω for maximum safe diode current. Image

Question

G1 Physics · Accepted Answer

Maximum diode current from the power rating is Iₘₐₓ = P/(diode drop) = 0.100/0.5 = 0.2 A. The resistor has 1.5−0.5 = 1.0 V across it, so R = 1.0/0.2 = 5 Ω.