Joule Thief

[TheNOP]

the only time it is not safe for your equipements are when you are trying to measure something bigger then the capability of that equipment.
you will shurely blow a fuse or fry your equipment if it ever happen.

and other is when the scale your equipment is set at is too low for the voltage you try to read, it might blow a fuse or blow a network resistor.
always make shure you choose the correct scale before applying the probe.

if you don't know what voltage to expect.
first ask yourself if it will be within the equipment maximum capability.

if yes, start at the highest scale. always start at the highest scale when unshure.

if no, try to estimate the maximum voltage you think you might get.
ex: 1 000,10 000, 35 000 volts in case of a tv flyback transformer
then calculate the minimum resistor values you should put in series with your probe to be safe.
always go for the highest resistance and lower it if you can't measure anything.

[jeanna]

Thanks theNOP,

I found I was doing that after I had checked with filling the cap. I am glad to know this is how to do this.

I will continue to use the cap first with a new toroid. I was worried about unexpectedly high results hurting the scope before I learn how to use it.

Thanks,

jeanna

[dog812]

Where is the best place to get torrids online?
I get mine from here locally, but i dont know if there prices are very good? http://rpelectronics.com Like $7 for 3..

[electricme]

@ Jeanna,

The question on the whereabouts to place your probes, I you are referring to circuir "orphanwithlights.jpg" which I think you are.

Looking at the right hand part of the diagram, one would place the clip to the earth being the neg battery side, probe could be placed anywhere else.
That said, we now tackle the substance of your question, relating to 2nd Tier.


OK, now for placing probes on the 2nd Tier side.
This side of the circuit is "floating" in regards to the 1st tier, as there is no actual physical electrical wire connection to it.
Any measurements will not be accurate, if you leave your earth cro clip, on the 1st tier.
.
So you need to establish a new "terminal point" to make your measurements, try cliping the probes earth lead to the (-) as seen which feeds the 2nd Tier circuit. make all your measurements from this "point".

Looking again at you new circuit you have two DC outputs being made from your 2nd Teir, The 1st output, is derived from the 2nd Torid itself, driving the single LED, the 2nd output, is derived from the 2nd secondary which is driving the 2 LEDs as seen.

So if you clip the probe earth end to the Negative, from your 1st Torid secondary output, as the base point to take readings, you should have success.



@all
I stayed up half the night watching the treddley bike race in France, it was the "cobblestones" event.
Well, this was exciting, sure was glad I wasnt a rider, those roads were extreamly bumpy, there were several bike crashes, the public in one town fell onto the track as bikes were going past, one camera bike collided with a narrow bridge, Giant figureines, lovely scenery, wild narrow streets, lots of history, yep full of surprises.

Next big event is the "Tour De France" I'm gona hook up my projection TV for that one.

jim


   

[Pirate88179]

Where is the best place to get torrids online?
I get mine from here locally, but i dont know if there prices are very good? http://rpelectronics.com Like $7 for 3..

Electronics goldmine.

http://www.goldmine-elec-products.com/searchprods.asp

Five 1" dia. for $1.  You can't beat that.  I hope this helps.

Bill