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The following formulae use it, assuming a constant voltage applied across the capacitor and resistor in series, to determine the voltage across the capacitor against time: Charging toward applied voltage (initially zero voltage across capacitor, constant V 0 across resistor and capacitor together) : = (/) [1]
Qi (/ tʃ iː / CHEE) is an open standard for inductive charging developed by the Wireless Power Consortium.It allows compatible devices, such as smartphones, to receive power when placed on a Qi charger, which can be effective over distances up to 4 cm (1.6 in). [1]
Inductive charging is also used in vehicles, power tools, electric toothbrushes, and medical devices. The portable equipment can be placed near a charging station or inductive pad without needing to be precisely aligned or make electrical contact with a dock or plug. Inductive charging is named so because it transfers energy through inductive ...
The diode and the switch are simplified as either a short circuit when they are on or by an open circuit when they are off. When in the off-state, the capacitor C is charged by the input source through the inductor L 1. When in the on-state, the capacitor C transfers the energy to the output capacitor through the inductance L 2.
Inductive charging pad for a smartphone as an example of near-field wireless transfer. When the phone is set on the pad, a coil in the pad creates a magnetic field [1] which induces a current in another coil, in the phone, charging its battery.
The energy (measured in joules) stored in a capacitor is equal to the work required to push the charges into the capacitor, i.e. to charge it. Consider a capacitor of capacitance C, holding a charge +q on one plate and −q on the other.
Instantaneous current declines to steady-state current as the capacitor reaches full charge. In the case of open circuit, the capacitor will be charged to the peak AC voltage (one cannot actually charge a capacitor with AC line power, so this refers to a varying but unidirectional voltage; e.g., the voltage output from a rectifier).
The amplifier offsets the input current using a feedback reference capacitor, and produces an output voltage inversely proportional to the value of the reference capacitor but proportional to the total input charge flowing during the specified time period. The circuit therefore acts as a charge-to-voltage converter.