energy supply vs consumption

[casrip1@gmx.com]

if i have a load with energy consumption of 2watts per hour, does that mean a 2 watt output with 4 volts and .5amps and a 2 watt output with 2 volts and 1amp both be able to power the device for an hour? or is there more to it than just having the same wattage? would i have to have a way to convert the volts to amps or amps to volts for an optimum operation?

 

[EdEarl]

Electronic devices generally have an optimal operating voltage, a maximum safe voltage, and a minimum operating voltage. Most devices will only use as much amperage as they require as long as the voltage supply is within minimum and maximum limits, which means you do not need to worry about too much current (usually--almost always).

 

Converting DC (direct current) voltage to a higher or lower voltage is more complex than converting AC (alternating current). To convert alternating current requires a transformer. To convert DC requires the DC be changed into AC, a transformer, and the AC changed again to DC. A transformer should be matched for both voltage and current, and the same is true for a DC to DC converter.

 

The DC to DC converter I described above is electronic. It is also possible to do the same job with a DC motor driving a DC generator.

Edited June 23, 2013 by EdEarl

[studiot]

if i have a load with energy consumption of 2watts per hour,

 

This is a misconception.

 

Watts are a unit of power, not energy.

 

Power already incorporates time so watts per hour is meaningless.

 

The unit of energy is the Joule.

 

1 Joule per second = 1 watt

 

So 3600 Joules per hour = 1 watt.

 

In electricity the quantity we call current also incorporates time so

 

current time voltage = power

 

amps times volts = watts

 

So yes 4 x 0.5 = 2 x 1 = 2 watts.

 

But see what EdEarl has said about your load and supplies.

 

Note that most supplies set the voltage and the current is determined by the load. You cannot have a power supply that sets both at the same time.

 

Does this help?

[EdEarl]

That one buys energy in KWh is confusing, because 1 KWh is 100 watts of power used for 10 hours (i.e., watt hours), 10 watts for 100 hours, or 1000 watts for an hour, etc. But, sometimes people say 1000 watts per hour (a colloquial use of per) instead of 1000 watts for an hour. However, the word per means divide by not multiplied by in scientific circles.

Edited June 23, 2013 by EdEarl