# What is the voltage of a cell phone charger?

For mobile phones and other mobile devices like the Kindle that charge with USB, the voltage is typically 5V. A laptop charger might be as high as 20V or 25V. You can usually find the voltage your device needs on the device itself, on the battery, or if all else fails, on the manufacturer's web site.
A.

### How many volts is a phone charger?

You could use a Lightning connector plugged into a computer (via USB), an iPhone charger connected to a wall socket, or an iPad charger connected to a wall socket. A PC USB charger delivers 2.5 Watts of power (5 volts at 500 mA). An iPhone charger delivers 5 Watts (5 volts at 1000 mA).
• #### Is a USB port AC or DC?

It is simply a USB cable, which allows my tablet to charge from a DC USB port in a car or laptop. Both sides have DC, so no conversion is required. Now, here is my tablet's AC charging solution. The same USB cable plugs in to a little black box that plugs in to an AC outlet – the box converts AC to DC.
• #### Is a 2.1 amp charger fast?

Most tablets require 2.1 amps to charge at a standard rate. Any time you apply a higher charge rate to the device, you can rapid-rate charge that device (e.g., using a 2.1-amp charger on a smartphone that requires only a 1-amp charger) This means the device can charge up to 20% faster than its standard rate charge.
• #### How much does it cost to charge a phone over night?

If you fully drained and recharged your phone everyday, then over the course of a year you would have to feed it about 2,000 watt hours, or 2kWh. At an average price of 12 cents that means that your phone uses about one quarter's worth of electricity per year.
B.

### How many volts is a USB port?

A USB port can give 500 mA output max provides 5 Volts x 0.5 Amo = 2.5 Watts. With real world efficency losses (nominally 80~90% efficent), you can provide a Higher Voltage with Less Current, or a Lower Voltage with More Current, but you can't create powerout of nowhere.
• #### How long does the battery last on a portable charger?

It is based on how long a battery will last when power is drawn constantly, e.g. a 2000 mAh battery will power a device drawing 100 mAh for 20 hours. Short for ampere, this is a unit of current, not a unit of charge. It describes the constant and average current that passes through the circuit.
• #### What is a 2a charger?

If you are talking about a USB charger, 1A is enough to charge most devices such as GoPros and Bluetooth headsets and phones, but tablets need 2A. (1A means 1 amp - a measure of electrical current - as others said. In the context of a charger, it means "twice as much" or "twice as fast", if the device can use it)
• #### How many amps does it take to charge a phone?

An iPhone charger delivers 5 Watts (5 volts at 1000 mA). A Retina iPad mini charger delivers 10 watts (5.1 volts at 2100 mA). While all of these will charge your iPad, using the USB connected to a PC will charge your Retina mini four times slower than if you used the iPad charger it came with.

Updated: 2nd October 2019