[HN Gopher] Make a Joule Thief (2002)
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Make a Joule Thief (2002)
Author : bariumbitmap
Score : 63 points
Date : 2021-09-05 12:56 UTC (10 hours ago)
(HTM) web link (bigclive.com)
(TXT) w3m dump (bigclive.com)
| nickcw wrote:
| Big Clive's YouTube channel is worth a watch if you like seeing
| electrical items disassembled and critiqued. It also has the
| occasional explosion and unusual cooking videos!
|
| https://www.youtube.com/channel/UCtM5z2gkrGRuWd0JQMx76qA
| lscotte wrote:
| Big Clive's channel(s) (he has a separate one for live streams)
| have some of my favorite content on YouTube. He's super down to
| earth and just has fun with what he does, never taking himself
| too seriously while being very knowledgeable.
| randombits0 wrote:
| * Anticipated explosions managed with the fire containment pie
| tin.
|
| Big Clive is an electrical engineer from The Isle of Man and
| has a very unique English accent, complete with local slang and
| idioms. He's a very engaging character and passes as
| entertainment, even without the electronics content. Genuine
| and occasionally heartfelt and up-lifting. :)
| gm3dmo wrote:
| His accent is quite common in Scotland. What's really cool is
| he has a brother "Ralfy" who also has a Youtube channel
| specializing in reviewing Whisky:
|
| https://www.youtube.com/watch?v=DWRyIShLRO0
|
| They are the Tappet Brothers of the 21st Century.
| lscotte wrote:
| I love your Tappet Brother's analogy - it's spot on. The
| videos they do together are hilarious in a way that only
| two brothers could be.
| agumonkey wrote:
| beside clive there's a bunch of special electrical oriented
| channels:
|
| - photonicinduction (warning, absurd levels of everything up to
| 11, borderline insane at times, but if you want to see ultra
| high everything, here's the channel)
|
| - styropyro, spiritual son of the above, but for everything
| lasers
| Stevvo wrote:
| It's a must watch for all the episodes that involve things
| inserted up assholes, even if electronics isn't your thing.
| HPsquared wrote:
| Reminds me of this video about LED light bulbs that continue to
| draw power even with the switch off. (Something to do with
| capacitance of the house wiring, the capacitive coupling is
| enough to make the bulb glow faintly even with the switch turned
| off)
|
| https://youtu.be/1uEmX5XClPY
| bariumbitmap wrote:
| Related submissions, although none have any comments:
|
| _Joule Thief_ (June 17, 2021)
| https://en.wikipedia.org/wiki/Joule_thief
| https://news.ycombinator.com/item?id=27540614
|
| _How to steal every last bit of juice from a battery_ (April 28,
| 2015) http://aeguana.com/blog/the-joule-thief/
| https://news.ycombinator.com/item?id=9451484
|
| _Joule thief - A minimal boost converter_ (January 25, 2015)
| https://en.wikipedia.org/wiki/Joule_thief
| https://news.ycombinator.com/item?id=8941971
| hasmanean wrote:
| This circuit is intriguing...a single transistor power converter
| that steps up the voltage to any value the load can take. It's
| more like a pulsed current source.
|
| It might be suitable for miniaturization.
| datameta wrote:
| Is it possible to build a circuit that keeps the same voltage
| while letting the current drop?
| yetihehe wrote:
| Yes and no (your question is invalid/underspecified), with
| voltage source (constant voltage), current is consequence of
| device power demand at required voltage. More power required
| at a given voltage, more current will flow. Less power
| required, less current will flow, but voltage stays constant.
| So, ALL voltage regulators are "dropping" current, so your
| question could be answered by "any voltage regulator, for
| example LM7805". But if some device requests some power and
| your regulator's power source can't provide that power, your
| voltage will drop.
| datameta wrote:
| Thanks for the explanation!
| ricksunny wrote:
| What are some of the most practical applications? I work in off-
| grid energy (solar) and would be interested in when/whether a JT
| can be more viable than, say, a boost DC/DC converter / linear
| current booster.
| Animats wrote:
| It _is_ a DC /DC converter. It's a basic switching power
| supply.
|
| I was hoping, from the name, for something that would pick up
| ambient RF and deliver a milliwatt or so. That would be useful
| for things that need minimal power and are a pain to connect to
| a power source.
|
| Such things have been around for decades. There's an
| Instructable for this.[1] Newer designs try to use more of the
| available spectrum.[2]
|
| [1] https://www.instructables.com/RF-Energy-Harvester/
|
| [2] https://www.teratonix.com
| spapas82 wrote:
| It would be great if this was available for purchase from
| somewhere. And if it also included an on off button! I've got a
| lot of dead batteries (because children toys) and it would be
| nice using them to get some light for night reading!
| blacksmith_tb wrote:
| There are lots of 1AA LED lights out there, I have a couple
| which are similar to this one (though this design looks nicer
| than the ones I have)[1]
|
| 1: https://www.tindie.com/products/sdp8483/multi-led-joule-
| thie...
| koala_man wrote:
| Why don't you use rechargeable batteries? I stopped using them
| in the 90s but switched back a few years ago. More convenient
| and less wasteful than single use batteries, higher capacity
| and longer device life than built in batteries.
| spapas82 wrote:
| They have so many toys (which use for so little each time)
| that it ain't really worth it to use rechargeable
| batteries... I am just buying a lot of normal batteries each
| time and install them whenever needed. I just don't know what
| to do with the empty (or seeming empty) ones.
| Sharlin wrote:
| Perhaps off-topic, and this may or may not be a popular
| sentiment on HN, but maybe they could do with fewer toys?
| At least fewer battery-operated ones? I mean, each and
| every one of us should be doing our part to not partake in
| unsustainable consumerism.
| hamburglar wrote:
| I've tried this but it's really hard to get the rest of
| the gift-giving family on board. My kids just get way too
| many toys these days. I use rechargeable almost
| exclusively though and try to keep on top of pulling them
| out of disused toys to put into newer toys. If a kid
| tries to use an old toy that I've taken the batteries out
| of (which rarely happens), I just give them more.
| bxparks wrote:
| I agree, NiMH rechargeables are better than alkalines in
| almost every way. They don't leak and destroy the
| electronics. They can be recharged 500-1000 times, so they
| don't end up in a landfill after a single use. They have a
| really flat voltage curve. They have lower internal
| resistance, so can provide higher currents than alkalines.
|
| I think the only exception might be in ultra low power
| devices which last over a year on a single charge. But even
| then, I am likely to use the more expensive NiMH, because I'm
| so fed up with leaking alkaline batteries.
| tzs wrote:
| Low self-discharge NiMH can last a long time in low power
| devices.
|
| I've got a pair of first generation AAA Sanyo Eneloops in
| my bathroom scale. They've been in there for 1028 days. I
| have a pair in the display unit for a pair of wireless
| fridge/freezer thermometers. That went 395 days.
|
| I've got first generation AA Panasonic Eneloops currently
| at 1079 days in one of the fridge/freezer thermometer
| sensors and 978 days in the other. 539 days in a humidity
| meter. 544 days in an analog wall clock.
| fencepost wrote:
| With a good charger (not the ones included in sets of
| batteries) you can also refresh them through programmed
| charge discharge cycles if you have batteries that aren't
| in great shape anymore.
| p1mrx wrote:
| Rechargeable AA/AAA batteries were always limited to 1.2
| volts, which works poorly in some devices. Now you can buy
| lithium ion cells that regulate down to 1.5 volts, so NiMH is
| basically obsolete. Alkaline can still make sense for things
| with multi-year battery life, like remote controls.
| veganjay wrote:
| I built a joule thief flashlight as part of a workshop at a
| security conference in 2018. We bought a kit that had all the
| parts, and then soldered them together. For a beginner soldering
| project, this is excellent.
|
| Unfortunately, I don't think the kit I built is still available.
|
| Here's some information I could dig up:
|
| - https://www.gigaparts.com/etow-humanalight.html
|
| - https://aa7ee.wordpress.com/2014/08/18/the-humanalight-a-fla...
|
| - https://swling.com/blog/tag/etow-humanalight/
| tzs wrote:
| A few years ago there was some new company (I vaguely recall that
| it may have been a Kickstarter or similar) touting something like
| this built into a shell that you could put an AA battery in, and
| the shell would still fit in most AA slots.
|
| They were way overselling its benefits, claiming you would get
| something like 6 times as much runtime out of your batteries, and
| it got a lot of negative reviews and debunking at EE tech sites.
|
| I wish someone would make one of these with that sleeve approach,
| not as some sort of miracle energy extended scam but rather as a
| voltage curve adjuster.
|
| A common non-rechargeable alkaline battery starts at about 1.5
| volts and over its useful life drops fairly steadily to a little
| over 1 volt, and then rapidly drops to near zero.
|
| A NiMH rechargeable starts at around 1.4, fairly quickly drops to
| about 1.3, then over most of its life drops fairly smoothly to
| about 1.2, then starts dropping faster to around 1.1, then
| rapidly to near zero.
|
| This is why you can use NiMH in devices designed for alkaline
| batteries even though nominally alkaline batteries are higher
| voltage. The device has to actually be designed to handle 1 to
| 1.5 volts, and the NiMH is in that range for nearly all of its
| discharge curve.
|
| This is also why some devices designed for alkaline report low
| battery on NiMH long before the batteries actually need changing,
| and still report low but useful battery level right up until the
| device stops working. They are estimating battery life by looking
| at the voltage and fitting that to the alkaline discharge curve
| to estimate how far the battery has discharged, and it makes the
| batter level meter on many devices close to useless if you use
| NiMH.
|
| It would be great if there were a sleeve you could put around
| your NiMH batteries that would dynamically raise or lower the
| voltage as the battery discharges to make it match the alkaline
| curve. Then your battery level indicator on your devices that
| were designed only for alkaline would work.
| Nextgrid wrote:
| What you're talking about is the Batteriser/Batteroo. It would
| actually work fine as a voltage stabilizer delivering a
| constant voltage all the way to the end, but the inefficiencies
| in power conversion would probably be a major downside (you're
| losing some energy on the conversion even if the device itself
| is powered off).
| a1369209993 wrote:
| > but the inefficiencies in power conversion would probably
| be a major downside (you're losing some energy on the
| conversion even if the device itself is powered off).
|
| You can get around this[0] by starting the power converter in
| series with the battery (so the load pulls current through it
| to start it up) although that's: a: complicated, b: more
| conversion overhead when it _is_ running, and c: rather
| difficult when you only have 1.5 volts (or 1 volt) to work
| with initially, compared to eg a 9-volt or 12-volt battery,
| which exacerbates problems a and b.
| /-[starter]-+---\ _+ | | | | Ks
| [regulator] [LOAD] | | |
| \----+----------/
|
| 0: At least to the standards of the quiescent depletion being
| a rounding error compared to the battery chemicals breaking
| down over time.
| p1mrx wrote:
| If you search for "1.5V rechargeable", there are lots of
| lithium ion batteries with electronic voltage regulators now.
| Some designs will step down to ~1V when nearly depleted, so
| that low battery indicators still work.
|
| I'm not sure if an NiMH sleeve was ever practical given the
| space constraints, but it's kind of moot now that better
| technology exists.
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