Wireless charging allows devices to charge without cables or connectors by using magnetic induction between two coils. Qi is the wireless charging standard that transmits power over short distances up to 4 cm. Smartphones can be charged by placing them on charging pads or stands that have transmitter coils, which induce current in receiver coils within the phones. While convenient, wireless charging has lower efficiency than wired charging and causes devices to heat up more. It also requires devices and chargers to have added electronics and coils, increasing costs. However, wireless charging eliminates the need for different charger types and cables, improving durability over time.