Look a little closer
See the mechanism
Two coils transfer energy; a receiver conditions it
Read the diagram steps
Power transfer. Alternating current in the pad coil induces voltage in the phone coil. A receiver rectifies and regulates that input for the device power system.
Receiver requests a stop. A control message can tell the pad to stop power transfer, including when charging is complete. The changing field disappears when transmitter excitation stops.
Original functional schematic; dimensions and motion are exaggerated, not measured. Basic inductive Qi path. No promised power, range or protocol timing. Receiver circuit basis: TI BQ51013C-Q1 product description.
Diagram basis: Wireless Power Consortium: How Qi Works.
Sources: Wireless Power Consortium · Texas Instruments
The coils do not need exposed contacts
The Wireless Power Consortium describes a transmitter coil and a receiver coil. The changing field links the two; electrical energy crosses the space between them through magnetic induction. The phone can therefore receive power through its casing without a cable plugged into it.
Sources: Wireless Power Consortium
The induced voltage is an intermediate step
A receiver still needs more than a coil. Texas Instruments' BQ51013C-Q1, for example, integrates a rectifier, regulator and digital controller. The rectifier converts the alternating input to direct current, while regulation conditions the supply. That output then serves the device's power system.
Sources: Texas Instruments
The receiver asks for changes
The phone sends control information back to the charging station. That feedback lets the transmitter adjust power transfer and stop when instructed, including when charging is complete. A pad is therefore part of a controlled system rather than a coil that blindly supplies the same power forever.
Sources: Wireless Power Consortium · Texas Instruments
The thing to remember
Induction crosses the gap; rectification and control make the received energy usable.
What this example leaves out
This is the basic inductive Qi path. Coil placement, supported power and control details vary by device and Qi implementation.
Sources & further reading
Source access dates are listed below. Manufacturer descriptions and patents support the specific constructions described, not every product.
- How Qi Works ↗
Wireless Power Consortium · Retrieved 2026-10-18 · Alternating transmitter current induces receiver voltage; phone sends control signals to transmitter.
Read entire knowledge-base explanation; embedded presentation not viewed. No current Qi-version performance claims. Independent review: web-tool open failed, but direct Invoke-WebRequest returned200 and full transmitter/receiver/control-signal text was read; no embedded presentation viewed. - BQ51013C-Q1 wireless power receiver ↗
Texas Instruments · Retrieved 2026-10-18 · Receiver AC/DC conversion, synchronous rectifier, regulation and feedback control to transmitter.
Read product Description and Features. Specific Qi v1.3 receiver circuit example; not a claim that every phone contains this chip.
