Magamp oscillator

On Tue, 3 Nov 2015 16:19:34 +0100, Piotr Wyderski
<peter.pan@neverland.mil> wrote:

>John Larkin wrote:
>
>> If you mean a DC powered circuit that oscillates using only passive
>> parts and diodes, no relays or such, I've never seen it done.
>
>I'm not sure if you can call a magnetic amplifier a passive part.
>It can exhibit admirable power gain, but needs to be powered by AC,
>for example:
>
>http://sparkbangbuzz.com/mag-audio-amp/mag-audio-amp.htm
>
>The guy claims it has the gain of 2000. So recently, I have
>started to wonder if you can use such a device as a DC-powered 
>oscillator. I agree, the answer "yes" would be a surprise, but
>maybe it is "yes" indeed?
>
>	Best regards, Piotr

You can also make an amplifier or an oscillator using varicap and
rectifier diodes, but it also needs an AC pump.

Since nobody has done what you suggest in about 200 years of
tinkering, I suspect it can't be done.

On Tue, 3 Nov 2015 15:31:04 +0100, Piotr Wyderski
<peter.pan@neverland.mil> wrote:

>legg wrote:
>
>> Magnetic amplifiers are conventionally effective in an AC environment
>> - the power source is already 'oscillating'.
>
>Hence my question, whether it would be possible to build an all-magnetic 
>circuit.
>
>	Best regards, Piotr

I challenge you to find the word 'oscillate' or 'oscillator' in any
text devoted to magnetic amplifiers or saturable inductor circuits.

Even one for motors and generators....come to think of it.

You may find scattered references to 'over-unity' devices, usually
ignoring the energy input to the practical circuits.

It's not blindness or some kind of intellectual tyranny - concepts of
gain, control theory and damping are readily applied, but 'passive
components'...are....just....that. You need a start-up mechanism that
can be seen by the reactive circuit elements, even at micro or nano
fabrication scales, for the DC-only application.

Once it starts, it might be carefully maintained through the
non-linear magnetics' opposing switching actions, the contribution of
capacitive reactances and probably some non-passive elements like
diodes to steer current.

And then, if youre very skillfull, it would do what most other
oscillators hope to do - almost nothing else.

RL

legg wrote:

> I challenge you to find the word 'oscillate' or 'oscillator' in any
> text devoted to magnetic amplifiers or saturable inductor circuits.

You don't need to challenge me, I have exactly the same
experience after nontrivial amount of googling. There's
nothing about it. Which is the reason I asked here, the
people inhabiting this newsgroup know a lot about all
kinds of crazy things.

	Best regards, Piotr

On Tuesday, 3 November 2015 14:54:00 UTC, Piotr Wyderski  wrote:
> nt wrote:
> 
> > so derive your ac with a spinning magnet/coil.
> 
> Yes, an Alexanderson alternator would be an option. :-)
> But how about a circuit without any moving parts. Doable?

Just use a mains transformer.

If you must run it off dc for some reason, thermal devices can oscillate to produce ac - getting the frequency up will be fun, but just about doable.

I don't know whether you'd consider an arc as a moving part, they can oscillate.


NT

On Tuesday, 3 November 2015 15:07:54 UTC, John Larkin  wrote:

> If you mean a DC powered circuit that oscillates using only passive
> parts and diodes, no relays or such, I've never seen it done. Except
> tunnel or some other negative-resistance diode.

If it can oscillate it exhibits gain. If it exhibits gain it's active.


NT

On Tuesday, 3 November 2015 18:03:19 UTC, Piotr Wyderski  wrote:
> legg wrote:
> 
> > I challenge you to find the word 'oscillate' or 'oscillator' in any
> > text devoted to magnetic amplifiers or saturable inductor circuits.
> 
> You don't need to challenge me, I have exactly the same
> experience after nontrivial amount of googling. There's
> nothing about it. Which is the reason I asked here, the
> people inhabiting this newsgroup know a lot about all
> kinds of crazy things.

If you've got gain and time delay, you can have an oscillator. I very much expect the reason no-one does it is that it's about as practical as mounting a gun on top of your head and trying to fight a battle. Possible yes, but sensible no, there are far better options.


NT

On 11/03/2015 10:54 AM, John Larkin wrote:
> On Tue, 3 Nov 2015 16:19:34 +0100, Piotr Wyderski
> <peter.pan@neverland.mil> wrote:
>
>> John Larkin wrote:
>>
>>> If you mean a DC powered circuit that oscillates using only passive
>>> parts and diodes, no relays or such, I've never seen it done.
>>
>> I'm not sure if you can call a magnetic amplifier a passive part.
>> It can exhibit admirable power gain, but needs to be powered by AC,
>> for example:
>>
>> http://sparkbangbuzz.com/mag-audio-amp/mag-audio-amp.htm
>>
>> The guy claims it has the gain of 2000. So recently, I have
>> started to wonder if you can use such a device as a DC-powered
>> oscillator. I agree, the answer "yes" would be a surprise, but
>> maybe it is "yes" indeed?
>>
>> 	Best regards, Piotr
>
> You can also make an amplifier or an oscillator using varicap and
> rectifier diodes, but it also needs an AC pump.
>
> Since nobody has done what you suggest in about 200 years of
> tinkering, I suspect it can't be done.
>
>
>
Well, tunnel diodes work.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

On 11/3/2015 12:03 PM, Piotr Wyderski wrote:
> legg wrote:
>
>> I challenge you to find the word 'oscillate' or 'oscillator' in any
>> text devoted to magnetic amplifiers or saturable inductor circuits.
>
> You don't need to challenge me, I have exactly the same
> experience after nontrivial amount of googling. There's
> nothing about it. Which is the reason I asked here, the
> people inhabiting this newsgroup know a lot about all
> kinds of crazy things.
>
>      Best regards, Piotr
>

   I don't know if this is helpful, but here is an oscillator that runs 
on 5.5mv B+. So it doesn't take much wiggle to work, now you just need 
to find out how to wiggle it with out the FETs.
Needs a core that will saturate at less than 0.40 ma somewhere. ;-)

> http://www.dicks-website.eu/fetosc/enindex.htm

                                 Mikek

On Tuesday, November 3, 2015 at 2:45:41 AM UTC-8, Piotr Wyderski wrote:
> Is it at all possible to build an oscillator entirely from
> non-linear magnetics (OK, solid state diodes are allowed)?

  Maybe, if you can find something with an "s" or "n"-shape knee in its reluctance curve. Metamaterial perhaps?


  Mark L. Fergerson

On Tuesday, November 3, 2015 at 6:52:18 AM UTC-8, tabb...@gmail.com wrote:

[on feasibility of building an oscillator with magnetic amplifiers]

> so derive your ac with a spinning magnet/coil.

I think a DC motor has a commutator, so there's a switch involved.
Easier, would be a common doorbell buzzer (again, magnetically
operated switch).

It's necessary to have feedback; a magamp has a DC control
input, so you need to get from AC output, through some kind
of rectifier, with a phase shift, to the input.
I nominate resistive heater/thermopile DC generator for the rectifier.
That way, everything but the phase shifter can be welded-wires construction.
Hey, it's gotta be RUGGED, to be impressive!