How does your Mobile Phone Charger actually work?
The technicalities
Technically, what we refer to as a phone charger is more of a power adapter that provide a power source to charge to circuitry in the mobile phone. They have been notoriously diverse with a wide variety of styles on the DC connector pin as well as in voltage – remember your phone running out of charge at work, and desperately looking for someone who had the same brand and make of phone as yourself so that you can restore power to it?
How a mobile phone charger works
Mobile phones and many other mobile devices rely on rechargeable batteries as their primary source of power. But, we need to understand the basics of batteries and battery charging to fully understand how our mobile phones charge.
Battery charging
All batteries and chargers function on the basic principle of converting stored chemical energy into electrical energy and vice versa. When you connect a battery to an electronic device, the chemical energy stored in the battery is converted into electrical energy as a result of a reaction within the battery. When we connect our mobile to the phone charger, this reaction within the battery is reversed and electrical energy is converted back into chemical energy stored in the battery.
Lithium-ion batteries
Most mobile phones use rechargeable batteries that house lithium-ion chemistry as a source of power. Inside this type of battery, there is a cathode (a negatively charged electrode) comprised of lithium metal oxide and an anode (a positively charged electrode) made up of carbon; they are separated by an electrolyte conductor. When a mobile phone powered by a lithium-ion battery is connected to the mains supply (via a mobile phone charger), the lithium ions in the battery flow FROM the cathode TO the anode.
When the phone is being used and disconnected from the mobile phone charger, the lithium ions flow in the OPPOSITE DIRECTION.
Different types of chargers
There are some different types of mobile phone chargers available but all of which use the same principle in charging the mobile phone battery. Standard wall mobile phone chargers use the electrical energy produced to charge the battery. Mobile phone car chargers use the electrical energy from the car’s battery to charge the battery and USB chargers use the electrical energy from the laptop or desktop PC to charge the battery.
Charging in stages
- The first stage of charging sees the battery’s voltage increase quickly and significantly due to the constant electrical current.
- Stage two is when this voltage peaks and the current from the charger begins to decrease.
- Stage three is when the battery is fully charge and the charger cuts the current off from the mobile phone
- Stage 4 is stand-by mode – in other words, the charger if it stays connected will supply a top up charge if and when the phone is used and the voltage of the battery drops below a certain level.
Mobile phone chargers are moving on at a great pace. Smart phones could soon be charged in your car through a wireless phone charging system (source: BBC website 20/12/12). Car manufacturer Toyota is looking to introduce a new charging system known as Qi (pronounced “chee”) in to one of its models. The smart phone would simply sit on a special mat and through magnetic induction, would charge the battery in your mobile phone. This method of phone charging could become main stream in new cars within months!