To safely discharge a capacitor prior to ohmmeter testing, what should be used?

Using a 20,000 ohm, 2 to 5 watt resistor to safely discharge a capacitor prior to ohmmeter testing is the correct choice because it provides a controlled way to discharge the stored energy without the risk of damaging the capacitor or endangering yourself.

A resistor of this value can effectively dissipate the charge accumulated in the capacitor without generating excessive heat, which could occur if a lower resistance were used. Choosing a resistor with a power rating of 2 to 5 watts is also important, as it indicates the resistor can handle the heat generated in the discharging process without burning out.

Discharging a capacitor by directly shorting its terminals is highly dangerous because it can lead to a sudden release of energy, potentially causing personal injury or damaging the equipment. Additionally, using an ohmmeter directly on an undischarged capacitor can result in incorrect readings and could also damage the meter.

In summary, employing a resistor of appropriate resistance and power rating allows for a safe and effective method to discharge a capacitor, ensuring both safety and accurate testing afterwards.