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To convert volts and amps to watts, you can use the formula:
Power (Watts)=Voltage (Volts)×Current (Amps)text{Power (Watts)} = text{Voltage (Volts)} times text{Current (Amps)}Power (Watts)=Voltage (Volts)×Current (Amps)Given:
So, 5V and 1.0A equals 5 watts.
To find how many amps and volts are needed to get 21 watts, you can use the formula:
Power (W)=Voltage (V)×Current (A)text{Power (W)} = text{Voltage (V)} times text{Current (A)}Power (W)=Voltage (V)×Current (A)This gives us flexibility with different combinations of voltage and current. If you know either voltage or current, you can rearrange the formula to solve for the other:
If you know the voltage:
Current (A)=Power (W)Voltage (V)text{Current (A)} = frac{text{Power (W)}}{text{Voltage (V)}}Current (A)=Voltage (V)Power (W)?If you know the current:
Voltage (V)=Power (W)Current (A)text{Voltage (V)} = frac{text{Power (W)}}{text{Current (A)}}Voltage (V)=Current (A)Power (W)?Do you have a preference for either the voltage or current, or are you open to different combinations?
Since we are aiming for 21 watts, we need to select either a voltage or current to solve for the other. I’ll provide a few possible combinations.
Assuming Voltage = 5V:
Current (A)=21W5V=4.2Atext{Current (A)} = frac{21W}{5V} = 4.2ACurrent (A)=5V21W?=4.2AAssuming Current = 1A:
Voltage (V)=21W1A=21Vtext{Voltage (V)} = frac{21W}{1A} = 21VVoltage (V)=1A21W?=21VAssuming Voltage = 12V:
Current (A)=21W12V=1.75Atext{Current (A)} = frac{21W}{12V} = 1.75ACurrent (A)=12V21W?=1.75ASo, you could use:
Let me know if you need a specific voltage or current!
Let's first calculate the energy your phone receives in 30 minutes using a 21W charger. Then, we'll find out how long it would take to deliver the same amount of energy with a 5V, 1.0A charger.
Energy is power multiplied by time. Since the 21W charger delivers power for 30 minutes:
Energy=Power×Timetext{Energy} = text{Power} times text{Time}Energy=Power×TimeConvert 30 minutes to hours:
30 minutes=0.5 hours30 , text{minutes} = 0.5 , text{hours}30minutes=0.5hoursNow calculate the energy:
Energy=21 W×0.5 hours=10.5 Whtext{Energy} = 21 , text{W} times 0.5 , text{hours} = 10.5 , text{Wh}Energy=21W×0.5hours=10.5WhFirst, let's calculate the power output of the 5V, 1.0A charger:
Power=5 V×1.0 A=5 Wtext{Power} = 5 , text{V} times 1.0 , text{A} = 5 , text{W}Power=5V×1.0A=5WNow, to deliver 10.5Wh of energy with the 5W charger, we calculate the time required:
Time=EnergyPower=10.5 Wh5 W=2.1 hourstext{Time} = frac{text{Energy}}{text{Power}} = frac{10.5 , text{Wh}}{5 , text{W}} = 2.1 , text{hours}Time=PowerEnergy?=5W10.5Wh?=2.1hoursIt would take 2.1 hours (or about 2 hours and 6 minutes) to deliver the same energy with the 5V, 1.0A charger as a 21W charger does in 30 minutes.
Thank you! I'm glad it worked out perfectly. If you have more questions or need help with anything else, feel free to ask!