How Much Electricity Is Generated by Passive RFID Tags?

How much electricity (voltage and current) does a passive RFID transponder generate upon receiving a radio signal, and on which factors are a tag’s electric power dependent?

—Jolene

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I’m not an engineer, so I reached out to Roger Stewart, an independent consultant who has designed RFID integrated circuits for a number of companies. Here’s his response: “The voltage and current generated in the tag increase if the tag is brought closer to the reader, but a modern passive tag is designed to operate (at maximum range) on only 1 microwatt of power—typically, at a power supply voltage of 1V with a current drain of about 1 microamp.”

—Mark Roberti, Editor, RFID Journal