Current draw

[violatorjf]

* Beginner Question *

When we state that a given emitter pulls XXXmah, is this a per hour rate? I am trying to read and understand more about the inner workings, and I constantly find myself coming across emitter X drawing 500mah and emitter Y drawing 750mah, and so on...

So it should just take a brief answer - thanks.

 

[Marduke]

* Beginner Question *

When we state that a given emitter pulls XXXmah, is this a per hour rate? I am trying to read and understand more about the inner workings, and I constantly find myself coming across emitter X drawing 500mah and emitter Y drawing 750mah, and so on...

So it should just take a brief answer - thanks.

Short answer, yes.

If an emitter draws 370 mA, it draws 370 mA per hour. This does not include, however, what any resistors or circuitry uses up in the system.

 

[TigerhawkT3]

No, that's not a per hour rate. Current, measured in amps (A or mA), is not dependent on time. This is why cells are rated at how many mAh they can manage, which is current for a certain amount of time. If an emitter is drawing 500mA, it's using 500mAh per hour. Try this link.

Think of a car engine. A 100hp engine isn't said to be using 100hp per hour. You could use that 100hp for an hour if you wanted, given enough gasoline.

 

[violatorjf]

No, that's not a per hour rate. Current, measured in amps (A or mA), is not dependent on time. This is why cells are rated at how many mAh they can manage, which is current for a certain amount of time. If an emitter is drawing 500mA, it's using 500mAh per hour. Try this link.

Think of a car engine. A 100hp engine isn't said to be using 100hp per hour. You could use that 100hp for an hour if you wanted, given enough gasoline.

Thanks, I'll read through all that tonight.

 

[DM51]

I think this will be better in 'Flashlight Electronics - Batteries Included', so I'm moving it there.

 

[Mr Happy]

Note: I've often seen people write mAh when they meant mA, and mA when they meant mAh. This can be confusing to newcomers, who won't immediately fix up the mistake in their mind.

In terms of water, you could think of mA as gallons per minute (gpm), and mAh as gallons:

5 gpm x 20 min = 100 gal
500 mA x 3 hours = 1500 mAh