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DMcFarlandInductor energy storage vs. capacitor energy storageI just read the article on DC power supplies. It explains the fundamental differences between linear and switch-mode power supplies. It explains that switch-mode PSs rely on inductors for temporary energy storage in the circuit. I know that capacitors and inductors can store energy in different ways and I’m wondering why switch-mode uses inductors. Saturday, January 29, 2011
11:46 AM

Comments (2)
SiliconFreak82Inductor energy storage vs. capacitor energy storageWhen you think about, it’s almost working like a ‘one-armed’ transformer. A single coil is serving the purpose of the primary and secondary windings of a conventional transformer, but the pulse-width-modulation (controlling the charge time) gives it a lot more flexibility in the ratio of transforming the voltage. Sunday, January 30, 2011
12:26 PM
KMW64inductor v. capacitor energy storageYour question made me curious so I did some research and came up with this: source Wikipedia - "An inductor is used as the energy storage device in some switched-mode power supplies. The inductor is energized for a specific fraction of the regulator's switching frequency, and de-energized for the remainder of the cycle. This energy transfer ratio determines the input-voltage to output-voltage ratio. This is used in complement with an active semiconductor device to maintain very accurate voltage control." Because an inductor converts electrical energy to magnetic energy as it charges, and then magnetic energy back to electric energy when it discharges, the discharge voltage can be made different than the charge voltage. With a capacitor there is no conversion of energy. The voltage it’s charged at will be the voltage it stores across its plates, and therefore the voltage that discharges from it. If you charge a capacitor at 5vdc it will discharge 5vdc (assuming no leakage), so it couldn’t be made to regulate that voltage. Saturday, January 29, 2011
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