Joule Thief

[resonanceman]

Yes the probes do have some voltage  protection.
There only supposed to let 3v get back to the soundcard.

Slayer

I got  this from your link

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# Built-in input protection circuit ensures its output to be less than 3V at all time to pretect the sound card from being damaged by excess input voltage, provided the input voltage is within the allowable range

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`

I  have not found  what  they mean  by allowable  range .
I would  love to   have a  PC based  O scope.
I  have never had a scope so  I am sure that I  will be making some  mistakes with it .
I am not  willing to  risk  my only computer to those mistakes .

The  USB  O scopes  that use   a PC for  memory  and  display look interesting   but  the  input  volltages  I have seen so far  are  between 20 and 100 V  even the more  expensive ones  I have checked.


I  had thought  that   any  real  scope  would  be able to handle more  voltage than  all these seem to be made for .


gary

Edit

I just found  a line  with  a  200V input ...  but it is   $ 720 to $ 1300    the  1  10  probes  $ 55
http://www.dataman.com/pc-oscilloscope.aspx

The  cheap one .  $ 720  is 60 MHz   

[IotaYodi]

Just watch those voltages. These are all digital too so the better the AD conversion on the soundcard the better. The bandwidth will be half of the sampling frequency.

Heres a new 25 mhz portable/benchtop digital scope with a usb connection for $300.  A little beefier at 300 volts and nicer.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170361338511&_trkparms=tab%3DWatching

[jeanna]

Well,
Since we are LOOKING for voltages that are much higher than 350v, it seems pretty risky.
Unless the top figure of 100v turns into 1,000v with a 10x probe.

I have not had any problems hurting my HP10 with the 10x probe. It quite happily reads those hogh voltages. But I am warned against them in the manual... But because the probe changes them to 1/10 of what they really are, I guess, this makes it work all right.

I am not willing to risk it for now.

I will wait.

jeanna

[resonanceman]

Just watch those voltages. These are all digital too so the better the AD conversion on the soundcard the better. The bandwidth will be half of the sampling frequency.

Heres a new 25 mhz portable/benchtop digital scope with a usb connection for $300.  A little beefier at 300 volts and nicer.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170361338511&_trkparms=tab%3DWatching

IotaYodi

Thanks for the link
This  was my current  favorite
http://www.saelig.com/PSPCEL/PS044.htm

I am looking  into  the one in your link
It is  bigger than  I  had  wanted ....... I kind of  like the  little box  and  the  idea of  using the computer for  display .
One thing  I  don't like  about  the  Pico it  requires XP or Vista .



I wonder  if the  USB connection with the scope in your link  will work with Linux
I do not like the way that  they have  listed the  max input voltage .  300v peak to peak .   still it is  better than most others I have looked at .

I am downloading the  manual .....



gary

[freepow]

 :)Hello, its freepow, Can anyone tell me, when making Joule thiefs... is it better to have an oscilliscope or digital multi-meter
I am thinking of purchasing a 10Mhz oscilliscope for $148 Aust, as i dont have heaps of money, can I measure DC or AC more acurately on a oscilliscope from a JT ??  or a Multi-meter ??
would a 10mhz oscilliscope help or would it be not worth having??
Any comments would be much appreciated, thanks