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Tutorial version of Joule-Thief

 

All,

I just uploaded a another copy of the JT, because I wnat to use it as a techng aid to introduce a family member to some EE concepts and LTspice. He just graduated high school and has no exposure but a lot of interest in electronics.

So having read the recent thread on the JT, I though it might be an excellent resource for him as it exposes transistor and switching theory and a lot of concepts in an easy to understand project that he can build and use my lab tools to verify the expected behavior.

In my posted version, derived from , I tried to added a second circuit to compare the effects of using a different transistor than the B549 in the reference article and I attempted to estimate the Joules being consumed (atfter all it is a Joule Thief.

If anyone cares to comment on how I might do this better (for the intended purpose), please do so.

Thanks,

Tim
John Woodgate
 

In message <kkbun5+ctqn@...>, dated Sat, 13 Apr 2013, Tim <thutches@...> writes:

I just uploaded a another copy of the JT, because I wnat to use it as a techng aid to introduce a family member to some EE concepts and LTspice. He just graduated high school and has no exposure but a lot of interest in electronics.
Too late! You need to start at Grade 2 or earlier. (;-)

So having read the recent thread on the JT, I though it might be an excellent resource for him as it exposes transistor and switching theory and a lot of concepts in an easy to understand project that he can build and use my lab tools to verify the expected behavior.
It may be me, but I don't find non-linear oscillators at all simple.

In my posted version, derived from , I tried to added a second circuit to compare the effects of using a different transistor than the B549 in the reference article and I attempted to estimate the Joules being consumed (atfter all it is a Joule Thief.

If anyone cares to comment on how I might do this better (for the intended purpose), please do so.
I favour sine-waves and audio frequencies, but we are all different.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
They took me to a specialist burns unit - and made me learn 'To a haggis'.

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
 

On Sat, 13 Apr 2013 15:47:49 -0000, Tim wrote:

I just uploaded a another copy of the JT, because I wnat to
use it as a techng aid to introduce a family member to some
EE concepts and LTspice. He just graduated high school and
has no exposure but a lot of interest in electronics.

So having read the recent thread on the JT, I though it
might be an excellent resource for him as it exposes
transistor and switching theory and a lot of concepts in an
easy to understand project that he can build and use my lab
tools to verify the expected behavior.

In my posted version, derived from
, I tried to added a second
circuit to compare the effects of using a different
transistor than the B549 in the reference article and I
attempted to estimate the Joules being consumed (atfter all
it is a Joule Thief.

If anyone cares to comment on how I might do this better
(for the intended purpose), please do so.
I just posted up an example I wrote some time back. I added a
comment or two to it before posting, though. It's in the Temp
directory and called Joule_Thief_jk1.asc.

It uses the basic energy equation to develop the expected
peak current required. It's ability to calculate the exact
frequency and the exact peak current given a specific
transistor is only approximate, though. The base resistance
calculation is only very approximate. Some tweaks are
included to allow closer approximations.

Note, the inductor coupling constant is given as 1 -- in
reality it never will be. Feel free to adjust the equations
to take a more realistic value into account.

Also, I have an additional paper I wrote on the Joule Thief
that includes details the above considerations plus others,
such as Bmax, in those cases where an air core isn't used.
The Bmax value places additional constraints on the choice of
inductance value vs frequency, to avoid saturation effects
due to volt-seconds (which the Joule thief doesn't not
require and works perfectly well avoiding.) If interested in
the paper, feel free to write and I will send it along in an
email (PDF form.)

Jon
 

Hi John.

Yes, it's sad that one gets a late start - my interest began at about age 14 as a ham radio operator.

What caught my eye about the JT was that it introduces the idea of switching which is more fundamental today than in my day. So learning about that at the start is important, especially if someone tricks you into thinking it is supposed to be easy. :-)

Yes I also prefer sine-waves - and tubes that glow purple.

Tim Hutcheson

--- In LTspice@..., John Woodgate <jmw@...> wrote:

In message <kkbun5+ctqn@...>, dated Sat, 13 Apr 2013, Tim
<thutches@...> writes:

I just uploaded a another copy of the JT, because I wnat to use it as a
techng aid to introduce a family member to some EE concepts and
LTspice. He just graduated high school and has no exposure but a lot
of interest in electronics.
Too late! You need to start at Grade 2 or earlier. (;-)

So having read the recent thread on the JT, I though it might be an
excellent resource for him as it exposes transistor and switching
theory and a lot of concepts in an easy to understand project that he
can build and use my lab tools to verify the expected behavior.
It may be me, but I don't find non-linear oscillators at all simple.

In my posted version, derived from , I
tried to added a second circuit to compare the effects of using a
different transistor than the B549 in the reference article and I
attempted to estimate the Joules being consumed (atfter all it is a
Joule Thief.

If anyone cares to comment on how I might do this better (for the
intended purpose), please do so.
I favour sine-waves and audio frequencies, but we are all different.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
They took me to a specialist burns unit - and made me learn 'To a haggis'.

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
 

Thanks Jon, I'll be having a look at what you did.

Tim Hutcheson

--- In LTspice@..., Jon Kirwan <jonk@...> wrote:

On Sat, 13 Apr 2013 15:47:49 -0000, Tim wrote:

I just uploaded a another copy of the JT, because I wnat to
use it as a techng aid to introduce a family member to some
EE concepts and LTspice. He just graduated high school and
has no exposure but a lot of interest in electronics.

So having read the recent thread on the JT, I though it
might be an excellent resource for him as it exposes
transistor and switching theory and a lot of concepts in an
easy to understand project that he can build and use my lab
tools to verify the expected behavior.

In my posted version, derived from
, I tried to added a second
circuit to compare the effects of using a different
transistor than the B549 in the reference article and I
attempted to estimate the Joules being consumed (atfter all
it is a Joule Thief.

If anyone cares to comment on how I might do this better
(for the intended purpose), please do so.
I just posted up an example I wrote some time back. I added a
comment or two to it before posting, though. It's in the Temp
directory and called Joule_Thief_jk1.asc.

It uses the basic energy equation to develop the expected
peak current required. It's ability to calculate the exact
frequency and the exact peak current given a specific
transistor is only approximate, though. The base resistance
calculation is only very approximate. Some tweaks are
included to allow closer approximations.

Note, the inductor coupling constant is given as 1 -- in
reality it never will be. Feel free to adjust the equations
to take a more realistic value into account.

Also, I have an additional paper I wrote on the Joule Thief
that includes details the above considerations plus others,
such as Bmax, in those cases where an air core isn't used.
The Bmax value places additional constraints on the choice of
inductance value vs frequency, to avoid saturation effects
due to volt-seconds (which the Joule thief doesn't not
require and works perfectly well avoiding.) If interested in
the paper, feel free to write and I will send it along in an
email (PDF form.)

Jon
John Woodgate
 

In message <kkhrsd+gjmc@...>, dated Mon, 15 Apr 2013, Tim <thutches@...> writes:

What caught my eye about the JT was that it introduces the idea of switching which is more fundamental today than in my day.
Agreed. But it makes for a steep learning curve.

So learning about that at the start is important, especially if someone tricks you into thinking it is supposed to be easy. :-)
Quite.


Yes I also prefer sine-waves - and tubes that glow purple.
Too high a B+, or they've gone soft! I once put 350 V on an acorn tube. Once!
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
They took me to a specialist burns unit - and made me learn 'To a haggis'.

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

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