Self running coil?

[ramset]

Well
My rejoined reciprocating angle arm
Blew out at the Deflatchulater Or I would definitely be in!

Very funny Luc [very]

Chet

[Magluvin]

Hey Luc

Actually I had sent that to a few people earlier today, I initiated the link as to say that it explained an idea that they had and that this guy did it already.
Here is his other one that adds to the vocabulary even more. Starts the same but a bit better lingo as it goes.

http://www.youtube.com/watch?v=lVZ8Ko-nss4&NR=1


Magslaffs

[Omega_0]

Thanks for clearing up the mosfet doubts.
I noted that the trace is exactly the same with coil disconnected, so the coil is essentially acting as an open circuit. One reason could be the high time constant (L/R) of the circuit. We don't have circuit diagram here, still assuming L=44mH, R=1ohm, V=1.2V, we get L/R as 44 ms.

Frequency is 18kHz so pulse cycle is 0.055 ms. and pulse on time is 55.5*22/100, or 0.012 ms.

Imax will be 1.2/1 = 1.2 amps
I at the end of 0.012 ms will be 1.2*(1-e^(-0.012/44)) = 0.0003 amp or 300 microamps !!

So you can see that the current rises to 300 uA and the pulse switches off. There is not enough time for the current to rise beyond your scope's detection threshold and it shows it as 0, which is right as 300 uA is practically 0.

You will need about a 100V supply to see any current flowing there. I'm pretty sure that the coil is not generating anything and merely acting as an open circuit, it can't switch on due to very high inductance and L/R and low voltage and tiny pulse width.

But I don't want to discourage you or anyone, so I'm leaving this thread now. It seems you did not like us "correcting" you, anyway. So simply assume that I'm wrong and go ahead, all the best.....

[gyulasun]

Hej Omega_0,

Please do not leave this thread... lol  You (or others) here need not feel the 'need for leaving'.  As long as conventional explanations are correct and scientific for clarifying the operation of a circuit, anybody should be welcome to come forward with correct contributions.

I agree with your calculations, one addition is Luc measured his toroidal coil DC resistance as 6.8 Ohm so the peak current was 1.2/6.8=0.176A and the the current at the end of 12ms was 322uA but this pretty much the same low current you got with the 1 Ohm assumption.

rgds,  Gyula

EDIT:  Just noticed, member EMdevices calculated the same order of small current (he got 350uA) at another forum.

[gotoluc]

Thanks for clearing up the mosfet doubts.
I noted that the trace is exactly the same with coil disconnected, so the coil is essentially acting as an open circuit. One reason could be the high time constant (L/R) of the circuit. We don't have circuit diagram here, still assuming L=44mH, R=1ohm, V=1.2V, we get L/R as 44 ms.

Frequency is 18kHz so pulse cycle is 0.055 ms. and pulse on time is 55.5*22/100, or 0.012 ms.

Imax will be 1.2/1 = 1.2 amps
I at the end of 0.012 ms will be 1.2*(1-e^(-0.012/44)) = 0.0003 amp or 300 microamps !!

So you can see that the current rises to 300 uA and the pulse switches off. There is not enough time for the current to rise beyond your scope's detection threshold and it shows it as 0, which is right as 300 uA is practically 0.

You will need about a 100V supply to see any current flowing there. I'm pretty sure that the coil is not generating anything and merely acting as an open circuit, it can't switch on due to very high inductance and L/R and low voltage and tiny pulse width.

But I don't want to discourage you or anyone, so I'm leaving this thread now. It seems you did not like us "correcting" you, anyway. So simply assume that I'm wrong and go ahead, all the best.....

Hi Omega,

please don't think that I'm not looking for corrections. This was the very reason I started the topic and why I had the ? at the end of the topic title.

Electronics is not my strong side so when I find an effect I usually ask for opinions from everyone. I have no problem learning something new.

@everyone, I may have been to quick to conclude when I added the 10K Ohm resistor on the 555 output. I looked at it today with the scope and it's way to much resistance for the mosfet gate to operate. It looks like the maximum resistance that can be added without affecting the gate would be around 200 Ohms.

I'm testing a few other things and will post what I find in a few days.

Thanks for all your interest and help.

Luc