current-controlled?

I can't seem to find any good information on what exactly this means with regards to flashlights and/or why it's a positive thing for them? I suspect the second part will be answered by knowing what it is but I'm just not able to readily find a good answer describing what it means...

I'm obviously new to the forum but am also, probably about equally as obvious at this point, new to collecting 'good' flashlights. I've always liked them and always have bought all sorts of cheap ones, much to the chagrin of my wife, and have now decided to step up and get more advanced and better quality ones that will last and be more fun anyway! That said I will no doubt be asking many questions in the short term so I hope it is as it seems to be that most, or at least some, are willing to help out and answer questions, give advise, etc... and possibly most importantly, know what they are talking about, and I look forward to learning and collecting!!

The first thing you might do is some researching here on CPF. For example, use google, cpf only, at the top of every CPF page, and write in current controlled and see what happens, then read some of the posts.

Bill

There are two ways to regulate the brightness of a led:

1) Always use maximum current, but turn if on/off very fast, if it is only on 1% of the time, the brightness is about 1%. This kind of regulation is called pwm.

2) Regulate the current with a (active) resistor or buck/boost circuit, this is called current control.


1) is the cheapest solution and easiest, but has lower efficiency than 2) and depending on the on/off frequency might also look like it flickers to some people and never use it around rotating stuff, that can be dangerous.

Bullzeyebill said:

The first thing you might do is some researching here on CPF. For example, use google, cpf only, at the top of every CPF page, and write in current controlled and see what happens, then read some of the posts.

Bill

Click to expand...

I feel dumb saying this, but the only search I had noticed till you said this was the one on the top right, never saw the other search on the left with the google/CPF options to check. I'll see if that gives better results. I tried it on the other smaller search bar and came up with nothing before I asked. I also tried using google and didn't really get any sort of definition or explanation, it came up with unrelated stuff, can't remember about what now... I'll try again though and see what I can find.

Thanks HKJ for the brief description. That helped quite a bit as I now have an idea of what they're talking about now, that it's a power saving mechanism...right? lol

wet11383 said:

Thanks HKJ for the brief description. That helped quite a bit as I now have an idea of what they're talking about now, that it's a power saving mechanism...right? lol

Click to expand...

It's not necessarily about power saving.

The main aim is to get constant light output over time without use of Pulse Width Modulation, a dimming technique that chops the light into very short bursts that some users find annoying.

A series resistor that limits the current flowing through a LED is, strictly speaking, a simple type of current control. LED light output will be initially bright, then gradually decline with time over the life of the battery.

However, as used on CPF, the term "current controlled" implies that a LED is driven at a constant, or nearly constant, current during most of the life of the battery powering it. So a current controlled LED will produce a constant, or nearly constant, output of light during most of the life of the battery.

.

Some devices are voltage controlled some are current controlled.

LED's are current controlled, any more volts than spec and poof.

So current controlled = you change the current to adjust the power, volts remains the same.

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After that you get in to the circuit design and HOW to control the current(pwm a resistor etc)