I just serendipitised onto this site almost 10 months after raving about it
at length - see below.
This time I found it via a search on the term      "coherer" and as I did
not mention it on the last pass, and as the site is every bit as amazing as
before. I'll shout its worth yet again.

For young people - especially teenages, this page could be life changing.
Needs adult oversight - some of these devices are seriously awesome.

FLAME (yes, fire) Triode amplifiers, DIY from raw materials semiconductors
and circuits built using them , magnetic amplifiers, TEA LAsers, unpowered
flying machines, .... AND coherers, including one built from two lengths of
wire and a hole in a workbench containing filings from a bolt.

As noted before - very few of these products are of practical value when
compared to readily avail;able modern implementations, but seeing the
underlying principles implemented with 'everyday stuff' should open up a
few mental filters. There's enough here to inspire some children towards a
life of science or engineering. Run ... !  And enough stuff to re-remind
old minds of the wonders underneath everyday products.

Very highly recommended.



                  Russell




On 6 February 2014 at 13:52, RussellMc <apptechnz@gmail.com> wrote:

> The most genuinely DIY electronics site I've ever seen - utterly
> astounding.
> Also utterly superb, but one mustn't put too many utterlys in the subject
> line.
>
> This is among the top few most amazing* websites I have ever seen.
> As  a starter introduction to young scientists / engineers and as a means
> of opening mental filters for the old and seen-it-all I've probably never
> seen better.
> Astounding.
>
>
> *       http://www <http://www>.sparkbangbuzz.com/ *
>
>                   Ref from James Newton.
>
> * Amazing rather than highly practical in most cases. As you'd expect, a
> transistor made from a piece of galvanised steel is probably going to be
> vastly inferior by almost any technical measure to a commercial product
> costing a few cents.  But demonstrating both that you CAN do it and HOW t=
op
> do it is priceless.
>
>
> DIY transistors - from raw materials - and raw materials that few have
> ever heard of in these roles.
>
> Semiconductor devices starting with galvanised iron sheet. Really!
>
> DIY tunnel diode equivalent.
>
> DIY FET
>
> FLAME amplifier (yes, the hot manifestation of combustion)
> Dual triode flame audio amplifier.
>
> DIY 40 metre transmitter based on DIY semiconductor :-).
> Output is about 50 microwatts - but
>
> DIY memristor
>
> Thermocouples - std copper/steel, but also Cu/Cu using oxide layer.
> Light an LED from output from N series connected (energy efficiency
> terrible)
>
> Levitation using static charge.
> Vastly greater levitation distances than anything I've seen using other
> methods - 1 metre plus.
>
> Corona amplifer
>
> Borax rectifier
>
> DIY CRTs !!!!!!!!!!!!!!!!!!
>
> DIY T.E.A. LASER
> Easier to make than cookies (he says)
>
>
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