*Question T7D10:
What reading indicates that an ohmmeter is connected across a large, discharged capacitor?*  

*Correct Answer is  A: Increasing resistance with time*  

### AI Response: (may contain errors)  

When an ohmmeter is connected across a large, discharged capacitor, the reading you observe will indicate the behavior of the capacitor as it charges through the ohmmeter's internal resistance. 

### Correct Answer: Increasing resistance with time

- **Explanation**: 
  - When you first connect the ohmmeter, the capacitor will start to charge from the ohmmeter's battery. Initially, the capacitor behaves like a short circuit, allowing a large current to flow, which results in a low resistance reading.
  - As the capacitor charges, the current decreases, and the resistance reading on the ohmmeter increases. This is because the voltage across the capacitor rises, reducing the current flow until it approaches zero, leading to a high resistance reading.

### Why the Other Choices are Incorrect:

- **B: Decreasing resistance with time**: 
  - This would imply that the capacitor is discharging or that the resistance is dropping, which is not the case. As the capacitor charges, the resistance increases, not decreases.

- **C: Steady full-scale reading**: 
  - A steady full-scale reading would suggest that the capacitor is either shorted or that the ohmmeter is not functioning correctly. A charged capacitor will not maintain a constant low resistance; it will show increasing resistance as it charges.

- **D: Alternating between open and short circuit**: 
  - This would indicate erratic behavior, which is not typical for a capacitor being charged. A capacitor will not alternate between these states; it will gradually charge and show increasing resistance.

### Useful Concepts:

- **Capacitor Charging**: The charging of a capacitor can be described by the time constant $\tau$, given by:
  
  $$\tau = R \times C$$

  where:
  - $R$ = resistance in ohms
  - $C$ = capacitance in farads

- **Behavior of Capacitors**: When connected to a circuit, a capacitor will initially allow current to flow (low resistance) and then gradually stop the flow as it charges (high resistance).

This understanding of how capacitors behave when measured with an ohmmeter is crucial for interpreting the readings correctly during the exam.