| Switch-mode AC-to-DC adapter | Mains AC; many models accept a broad range such as 100–240 V AC | Rectifies AC to DC, switches it at high frequency, then transforms and regulates it to a lower DC voltage. | Regulated DC, commonly 5–20 V depending on the adapter and connected device. | Phones, tablets, routers, and other electronic equipment. | Output voltage, current capacity, connector, and safety certifications must suit the device. |
| USB-C Power Delivery charger | Mains AC through an AC-to-DC adapter | A switching power supply creates regulated DC; the charger and device communicate to select a supported USB Power Delivery voltage and current. | Common fixed voltage levels include 5, 9, 15, and 20 V; supported power depends on both devices and the cable. | Compatible phones, tablets, laptops, and other USB-C devices. | The negotiated output is limited by the capabilities of the charger, device, and cable. |
| USB-A regulated charger | Mains AC through an AC-to-DC adapter | Converts mains power to low-voltage DC and supplies it through a USB-A port; some designs use charging signals to support higher current. | Typically 5 V DC; available current varies by charger and charging standard. | Older or compatible phones, accessories, and small electronics. | A USB-A port does not by itself guarantee a particular fast-charging capability. |
| Wireless inductive charger | Low-voltage DC from an AC adapter or another power source | Electronics create alternating current in a transmitter coil. A nearby receiver coil picks up the magnetic field, and the device rectifies and regulates the induced power. | Power is transferred across a short gap; the delivered level depends on the compatible charging system, alignment, and thermal limits. | Compatible phones, earbuds, and other small devices. | Coil alignment and heat affect efficiency; some energy is lost during transfer. |
| Lithium-ion battery charger | A suitable DC source, often supplied by an AC-to-DC adapter | A charge-control circuit monitors battery voltage and current. Many lithium-ion cells use a constant-current phase followed by a constant-voltage phase, with termination and protection controls. | A controlled charging current and voltage selected for the particular battery chemistry and cell configuration. | Portable electronics, rechargeable tools, and battery packs. | Use the correct charging profile; battery voltage and chemistry determine safe limits. |
| Solar charge controller | Variable DC from a solar panel | Regulates panel power to charge a battery safely. PWM controllers switch the panel connection; MPPT controllers adjust the electrical operating point and convert excess voltage into charging current. | Controlled DC matched to the battery’s charging requirements; available power varies with sunlight and panel conditions. | Off-grid systems, portable solar setups, and solar-powered battery charging. | Controller type, panel ratings, and battery chemistry must be compatible. |
| Linear charger or regulator-based charger | DC at a voltage above the required charging voltage | Uses a linear control element to reduce and regulate voltage or current; excess energy is mainly dissipated as heat. | A controlled, relatively low-power DC charging output. | Small devices and circuits where low electrical noise and simple design are useful. | Generally less efficient and more heat-sensitive than a comparable switching charger. |