why doesn't the current circuitry on data sheet match the current on tailcap?

xchcui · Mar 6, 2013

hello

when we read the data sheet of some flashlights we can see(among all the other spec.)a spec. which said"circuitry"and it gives a specific value of current.
but when i read the previews on the flashlights i see ,each time,that the current are much much more on measurment.for example if the data sheet say"circuitry-600mA",the current when measure the flashlight is practical 1400mA.
why doesn't the current,when measured on tailcap,is matching to the current in the data sheet?what does the spec.-"circuitry"actually,mean?

thanks in advance.

shelm · Mar 6, 2013

current is a function of cell voltage and once the light is turned on the cell voltage can be considered a function of time although physically this is wrong so basically current is a function of time which means that any given point in time the current differs from the minute before unless it is a true constant current driver.

true constant current drivers are super rare. you can sometimes find them in cheap ebay china lights.

amanichen · Mar 6, 2013

Using your numbers as an example, for instance the 600ma might be the output to the led from the circuit, and 1400ma is the input current to the driver through the circuit.

This could possibly indicate either a very inefficient circuit, or a boost circuit where the battery has a lower voltage than the led it is powering.

Also, many light companies might not give accurate specs for their products, especially if they are on the lower end of the price scale.

xchcui · Mar 6, 2013

thanks for your replies.
you right and i understand that the current is always changes(unless it is true constant current)
but what they are mean when they say,for example:"circuitry-600mA"? base on what they state that 600mA?on what situation is 600mA?what is it suppose to tell me?i thought it is indicate the max current in the flashlight.but the measurment on tailcap say 1400mA:thinking:

i forgot to mention that i am talking about simple direct drive flashlights without regulator.so it is,obviously,doesn't indicate the constant current value.

shelm · Mar 6, 2013

xchcui said:
thanks for your replies.
you right and i understand that the current is always changes(unless it is true constant current)
but what they are mean when they say,for example:"circuitry-600mA"? base on what they state that 600mA?on what situation is 600mA?what is it suppose to tell me?i thought it is indicate the max current in the flashlight.but the measurment on tailcap say 1400mA:thinking:

i forgot to mention that i am talking about simple direct drive flashlights without regulator.so it is,obviously,doesn't indicate the constant current value.

i understand your confusion.
because i don't understand the "circuitry-600mA" specification either.

let be noted that premium flashlight brands do *not* state such a thing.

so.

which flashlight brand are we talking about??

xchcui · Mar 6, 2013

i am not necessarily talking about specific brand.and it is also shown on the data sheet of expensive flashlights.when the flashlight is with constant current regulator it says"circuitry-constant current 2500mA"or use,on other case,the term"digital regulated 2500mA".and that i can understand what its mean.
but the term "circuitry-600mA"(or other value)is shown only at direct driver(no regulation) flashlights data sheet,and because that i ask those questions:

but what they are mean when they say,for example:"circuitry-600mA"? base on what they state that 600mA?on what situation is 600mA?what is it suppose to tell me?i thought it is indicate the max current in the flashlight.but the measurment on tailcap say 1400mA:thinking:

shelm · Mar 6, 2013

xchcui said:
and it is also shown on the data sheet of expensive flashlights.

no it's not.
premium brands don't do this.

xchcui · Mar 6, 2013

shelm said:
no it's not.
premium brands don't do this.

i saw this term"circuitry-_______mA" on cheap flashlights datasheet,i saw it on expensive ones(compare to the cheaper ones).
but i didn't said premium brands,i am not an expert of brands.
and,please,i will very appreciate if we can focus on my question.i am not want to get into arguments,it is not my purpose,i am only need an explaination to my question.

thanks in advance

shelm · Mar 6, 2013

okay i am giving up.
i'm out.

xchcui · Mar 6, 2013

no problem,shelm.thanks for your reply and your time

i hope someone of the cpf members can help me with that question.

PocketBeam · Mar 7, 2013

I suggest you give a specific actual example...

xchcui · Mar 7, 2013

ok.i got the answer from other reliable source.and i am sure the answer is right.
the meaning of the term"circuitry _______mA"refer to the max current on the high mode.
thank you,anyway,for trying help me with that question.

best regards

why doesn't the current circuitry on data sheet match the current on tailcap?

xchcui

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shelm

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amanichen

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shelm

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xchcui

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xchcui

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