Those latest unusually bright/efficient flashlights, be used to make generator

[e2matrix]

  no, I'm not interested in any solar-cell effect, in regard to these flashlights

  I thought that since these latest flashlights contain JT like circuits,  so they are high-performance  JT like circuits pre-built(  since I cannot build anything ),    that it may be possible to,  for example :
>snip<
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Ok I misunderstood your intention with the flashlights.   I've been a flashlight collector for many years and have a ton of LED lights.   Most have such miniaturized circuit boards I doubt you will want to tackle using them.  I can't say I've seen any sign they use JT type circuits either but I could be wrong.   I've had quite a few lights taken apart and most use simple circuits to regulate the voltage output to match the LED voltage rating and some can vary the current for different brightness levels but as smoky2 said they all need batteries and while a few people here made some super high efficiency JT circuits I don't believe any were OU with one possible exception I know of and that one was never able to be duplicated.   You'll probably do better to build your own JT circuit or even get one of the many JT kits available (at places like eBay).  Beware though 'Joule Thief' has become somewhat of a 'buzz' word often used to sell items like DC-DC converters which may not even have real JT circuits and those that say they don't have an inductor are most likely not a Joule Thief.   

[postingsite]

   @e2matrix

   Actually, I don't even know if a JT circuit would be required for my idea,  since you mentioned earlier :

Older and cheap LED flashlights used pulsed modulation but those tend to create a strobe effect when moving them or moving something in front of the light rapidly so they are not used much now unless the pulse frequency is very high.   

   maybe one of those very dated LED flashlights would do,  for pulsing coils on cores,  etc

   ( I once had one of those very common small keyring-flashlights, that only had one LED,  and a button-cell battery,  no other circuitry    )
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   just to add,     an alternative to using these circuits( if you want to try and use the ones from a flashlight ) to power coils on cores,  would be to use them to power :

   A TPU like device,  basically,  is based( from the little I know ) on the principle of winding a wire( Wire-A, which will conduct current ),   around another wire( Wire-B, which will also conduct current ),     so that both the coil( Wire-A ),  and the core( Wire-B ),  will both carry the current.

     This may work by the coil( Wire-A ),  forcing the core's( Wire-B ) field back into itself( back into the wire ),  and thereby inducing( or generating ) surplus current into the device.

    I don't know if there's both,  pulsed,  and  non-pulsed versions of  TPU devices

     There is an interesting wiring diagram on the web-link below, that link takes you straight to the exact post that the diagram is on,   but you would think it would be easier to just design your own circuit for such a simple idea
    http://overunity.com/712/the-master-of-magnetics-steven-mark/msg63797/#msg63797

     Another interesting wiring diagram for the TPU,  but I can now only access that diagram by using the following  command in  google-image-search ( Note,  by using the  "site:" command in the search,   to only search in the specified webpage )
   site:.http://overunity.com/2235/ottos-replication-of-steven-marks-tpu/90/
    OR
   https://www.google.es/search?q=site:.http://overunity.com/2235/ottos-replication-of-steven-marks-tpu/90/&rlz=1C1AOHY_enES712ES712&source=lnms&tbm=isch&sa=X&ved=0ahUKEwik_rC5vsLZAhUIcRQKHdxZBbQQ_AUICigB&biw=1024&bih=485

[sm0ky2]

the primary of the tpu is a multiple parallel path receiving antenna
tuned to a specific frequency
and with an intrinsically low resistance
the secondary coil is a capacitive inductor
and the 3rd is an inductively coupled output
the 3 act in resonance, to amplify the input signal


The input signal is from a capacitance larger than that of the tpu.
Your source must meet this requirement


TPU is not "self-powered"
Steven Mark tells us what his source is.
The capacitance was calculated for us by Tesla.


Winfred Schumann gives us the fundamental frequency


SM therefore gives us an (parallel) antenna length of 2x(1/f)
Where x is a whole number integer
And F is 7.83