Basic question about regulation

[MT7]

Hey everyone,
I don't know a lot about electronic,regulation etc, and someone told me that in any flashlight,also if it unregulated,when I turn off the flashlight and turn it on again the regulation is restarting and it run on 100%- max output,again. is it true?
if it's true,why is regulation so necessary?
for example,if my flashlight is unregulated,and after 15 minutes it's run on 50% of the brightness,and I use it Continuously for 15 minutes,if I will turn it off and turn it on again,will it back to the max output? (100%)
is it true in any flashlight? or is it true to only several flashlights?
thanks advance...

 

[Chicken Drumstick]

Regulation means different things for different lights. What torch are you referring to specifically?


Often on CPF 'regulation' will be meaning constant output regulation. So the torch will remain a constant brightness and then switch off (step down to a lower mode).

Incan torches and directly driven LEDs will slowly dim as the cells voltage drops. However if you are using NiMh or Lio-ion cells then the drop off might be gradual and quite different to torches of old.


However other lights might be regulated to maintain a lumen output for a set period of time then drop down to lower levels, or to maintain similar performance on different battery chemistry's.

There are also thermal regulation, where the torch will reduce output to maintain safe temperatures. A similar practice might be used to prevent over discharging certain battery types.


Here are some examples of output regulation (thanks to Selfbuilt for the first two images). As you can see the output on most of the lights stays almost the same for the entire duration, when the cells get low instead of dimming they'll shut off or only work on low mode.

In this example you can see a lot of the lights step down or have a gradual step down to a constant state. This is usually because they are being overdriven/driven really hard and heat and reliability could be issues. The lights 'regulate' and lower their output to a safer constant sate.

Here we have a different kind of regulation, this is a Mini Maglite Pro+. The MagLite doesn't do constant output regulation (likely due to heat build up and to extend runtime). But the thing to note here is how the different cell types all perform similarly. It's regulated to given constant performance no matter the powersource.

The different here from direct drive is, if you turn a Mini Mag Pro+ off and on again it'll restart the regulation from the beginning. This means if you want max output it is available. However the gradual reduction in output is likely to be difficult to detect in real world use and it won't start to drop until 3 mins of continual use.

A directly driven light will dim over time and switching off and on again will have no real affect to output (bar minor cell generation affects).

 

[shadowjk]

Then there's also a mode which isn't shown in the graphs above, where the light is regulated to constant brightness for as long as the battery can supply sufficient power, but instead of switching off or stepping down to a lower brightness when the battery no longer can supply enough power, it continues to output the maximum the battery can provide, which results in a gradual dimming.