What hazard exists in a power supply immediately after turning it off?
Circulating currents in the dc filter
This answer is incorrect because circulating currents in the DC filter are generally not a significant concern immediately after power off; they are more relevant during normal operation to smooth out the output current.
Leakage flux in the power transformer
This answer is incorrect as leakage flux in the power transformer is more of a concern during operation and not immediately after turning off the power supply.
Voltage transients from kickback diodes
This answer is incorrect because voltage transients from kickback diodes are a concern related to inductive loads and switching events but not specifically a hazard immediately after power off.
Charge stored in filter capacitors
This answer is correct because the charge stored in filter capacitors can remain for some time after power is turned off, creating a significant shock hazard.
Explanation
When working with electronics and radio equipment, it’s critical to understand the various hazards that can exist even after you turn off the equipment. One significant hazard in a power supply that could persist immediately after it has been turned off is the charge stored in the filter capacitors. Capacitors are electronic components that store electrical energy, and in a power supply, they help to filter and smooth out the output voltage. Even after the power is switched off, these capacitors can retain a substantial charge. This stored charge can pose a risk of electric shock if you come into contact with the capacitor leads or associated circuitry. Therefore, it’s essential for anyone working with power supplies to take precautions by properly discharging capacitors before performing any maintenance or repairs.
T0A11 2022-2026