My negative resistance oscillator Experiment

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My negative resistance oscillator Experiment

Postby Harry Dalek » Sat Jun 01, 2013 2:08 am

I got interested in making a home made type of Semiconductor made from in my case a galvanized nail .

I think its pretty interesting making an oscillator from a 2 pin device that you can make from junk .

How its made is you have to heat the nail with propane torch ,,,,,,on the other side around the nail zinc oxide is formed when it cools down and black spot of negative resistance you can see and some times not .

I also found if you don't have a torch a welder works as well with short welds to the nail it heats it enough to form the stuff .


Heres the circuit i am using apart from the rf part V cap and coil just doing AF ,the other coils in the picture are my magnetic amp transformers i am working on .

I am using more voltage than in the schematic 12 to 24 volts in the larger video you can see how touchy it is to adjust to get going ...also the wave form gos from nice sine wave to something a little more messy i suppose it could be the wire touching more than one negative resistance spot on the nail .

I saw one fellows design he had puts hes device in a large glass fuse to keep if safe ,i like that idea !

Most others i have seen doing this use galvanized sheets cut thin to make the device and i can say thin is good heating the metal would be harder if to thick ..it has to get pretty hot to the point the zinc starts to spit then you know its made the negative resistance dark spots on the metal ...

Simple thing but it is touchy to work out .
Attachments
negative oscillator.jpg
circuit i am using apart from the V cap and coil for RF
negative oscillator.jpg (12.33 KiB) Viewed 1607 times
Nail.JPG
Nail.JPG (398.77 KiB) Viewed 1607 times
negative resistance.JPG
This test i got a nice sinewave
negative resistance.JPG (428.35 KiB) Viewed 1607 times
P1050464.mpg
Here is the oscillator working
(3.55 MiB) Downloaded 116 times
P1050460.mpg
This video shows how touchy the device is to get going really needs a good casing to neaten it up
(12.37 MiB) Downloaded 103 times
P1050453.avi
Got a better sine wave on this go which i think on the others look messy could b e due to the wire connecting to more than one negative resistance spot on the nail
(3 MiB) Downloaded 101 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Harry Dalek
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Postby Harry Dalek » Thu Jun 06, 2013 6:08 pm

Still playing around with the zinc oscillator and tried to make a compact housed version but they are so touchy a little knock and it stops working .

The plan was to line it up working and hot glue it in place well the working part works gluing part not so good !

i made a few different versions to try but i think as in the old cat's whisker detector i think you really need the adjustments for something like this after trying a few times .

One last thing i tried a trany on the circuit just using the collector and emitter and that worked as well .

Home made parts are interesting but hard
:roll:
Attachments
P1050480.mpg
adjusting the oscillator frequency
(2.38 MiB) Downloaded 109 times
1.JPG
This version worked still very hard to get housed and working
1.JPG (417.71 KiB) Viewed 1581 times
2.JPG
This one i couldn't get going
2.JPG (324.83 KiB) Viewed 1581 times
3.JPG
i had a bit of luck with the small one but stopped working after a bit pot luck adjusting them !
3.JPG (380.26 KiB) Viewed 1581 times
pw_xtal_experimenters_hdbk.pdf
very old magazine on cat's whisker detectors
(2.3 MiB) Downloaded 151 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Metallica Man X » Thu Jun 06, 2013 7:26 pm

Homebrew parts may be hard, but darn do they look cool! Those ones in the fuses look totally pro 8)
I mostly lurk..don't be surprised when I actually post!
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Postby Harry Dalek » Thu Jun 06, 2013 9:59 pm

Metallica Man X wrote:Homebrew parts may be hard, but darn do they look cool! Those ones in the fuses look totally pro 8)


Very very hard my friend and a touch frustrating in the mix as well.

The Tiny fuse worked for a bit i was trying little cut out bits of zinc cut up nails what ever i had ..trouble is you need to hit just the right spot for it to work ...and just touching ever so slightly even at that .

I think its working via the negative resistance spots on the zinc like a very close spark gap or it seems like that ...

The last go i was hopeful for a housed working version but again very frustrating i know how those people who made early crystal radios must of felt like trying to adjust it to work ...oh well a bit side tracked off the magnetic amp just wanted to see if i could make a useful oscillator apart from the generator .

BTW the floppy drive generator gives at least 120 volts it will partly light a 240 volt globe .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Harry Dalek
"Fester! Don't do that to 'Thing'"
 
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