1. The problem statement, all variables and given/known data A pair of bare copper wires a, b is attached to a basement wall to detect the presence of moisture. Design a circuit, using a darlington transistor, to turn on an LED if the current flowing between the wires due to the moisture exceeds 10μA (use a current-sensing resistor to convert the current into a voltage which is then sensed by the darlington transistor). Use a 5V supply. Indicate component values. 2. Relevant equations None. 3. The attempt at a solution R = V/I = 5/10 = 0.5MΩ. The correct answer for the earthed resistor is 100Ω but I dont understand how to get this.