1. The problem statement, all variables and given/known data A moving coil ammeter is to be adapted to detect small alternating currents. Which of the diagrams shows how a diode could be connected in order to make the conversion ? (Options shown in attachment) (Ans: (3)) 2. Relevant equations 3. The attempt at a solution I am not sure if I understand the problem. What does it mean by "detect small currents"? Also, it doesn't state if the diode are considered to be ideal or not? But I think I am supposed to consider them as ideal. There are my thoughts: Circuit (1): The diode is non-conducting if + at the upper terminal and - at the lower terminal, so all the current pass through the ammeter. If the signs are switched, no current passes through the ammeter as the diode is now conducting. Circuit (2): Opposite to the functioning of circuit (1). Circuit (3): If + at the upper terminal and - at the lower terminal, the diode is conducting and ammeter records a reading. If the signs are switched, the circuit gets open and no current through ammeter. Circuit (4): Opposite to the functioning of circuit (3). But I am not sure which option to select as answer. Any help is appreciated. Thanks!