Joule Thief

[resonanceman]

@ all interested in a USB Digital Storage Oscilloscope (DSO):

The discussion got me interested in doing a quick on-line search for USB DSOs.

I found this British firm:

http://www.picotech.com/oscilloscope-specifications.html

http://www.picotech.com/computer-oscilloscope.html  ( PicoScope 3200,  £399.00, $658.35, â,¬466.83 )

The PicoScope 3200 is a bit expensive, but its specifications look good. Farnell sells it, so chances are high that it works.


@ Gary (resonanceman) and all who want 2 channels on a scope:

On my DSO-2100 the "ground" of the two channels is the same, which limits the simultaneous use of the two channels. Many inexpensive USB DSOs with two channels will be constructed in a similar way.

If the two signals I want to measure have the same "ground", I can see them together in different colours (which is very nice); if not, I will connect something in my circuit which should not be connected or one of the measurements will be meaningless.

The secondary coil in a Joule Thief type circuit behaves differently or fails when you tie it down to the same "ground" (battery pole -) as the Joule Thief circuit. Meaning, I can not measure the signal on the secondary together e.g. with the signal over the collector - emitter with my DSO-2100.

Two channels are good but you have to think before connecting two probes to your circuit.


@ all who like hand held scopes:

The inexpensive hand held scopes have a very limited frequency range (5 to 10 MHz) and a very limited resolution (on screen and in the memory).

The very good products from FLUKE are expensive:
http://us.fluke.com/fluke/usen/products/categoryoscill?trck=scopemeter

Greetings, Conrad

Conrad

I am very glad  to learn about  the  common  ground  before I bought.
I think it is much more valuable  to have  to related  signals on one  scope..........so you can see what happens to one when you   change the other.
It  would   be possible  to see the  changes with 2 separate scopes.....but  it would  be alot harder to see than with   a good 2 channel scope.

Do you know  the terminology  to use  when looking for  a scope  with 2 separate  grounds.
I see on your pico scope link   3425  has differential  inputs ..... could that  be the separate  grounds? ........it looks  slow  and expensive.......but then again it is 4 channels.



gary

[giantkiller]

I have one of their DSO-2090 usb scopes and it broke within warranty period. The company has not to this date replied back to me therefore I cannot recommend this company. I contacted Beigly electronics and hantek in China. They do not answer. Put your money elsewhere.
There are better companies to deal with.

Thanks freepow

Here is one I have been looking into.
I am checking on its max input voltage......I see input protection is diode clamping......If I understand that right .....any voltage over the  clamping voltage will  be drawn  off....... That sounds like a good idea to me.

I  found out about this on another thread.... gotoluc  has one  and  likes it.....

http://cgi.ebay.com/DSO-5200-50GS-S-PC-USB-digital-storage-oscilloscope_W0QQitemZ140324893670QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item20ac03f3e6


gary






                           

[conradelektro]

@ Gary (resonanceman) and other scope seekers:

The "differential input" seems to be the magic for placing multiple probes on a circuit.

This article explains a lot:

http://www.tiepie.com/uk/classroom/Measurement_basics/DifferentialMeasurements.html#Differential

http://www.tiepie.com/uk/products/ (British company)

It looks like one has to invest several thousand Euros to get something good.

And it needs some experience to use an oscilloscope in the right way. I am glad that I started with a comparatively reasonable scope (the DS-2100, which costed together with the three probes I bought about 350.-- Euros in 2006). Now I know a bit more and can think about upgrading.

I am convinced that one has to go for a "digital storage oscilloscope" (DSO) which has an USB interface. Connection to the PC is a must for documenting the results and for communicating them to others.

It is less expensive to buy a dedicated simple laptop (second hand) together with an USB-DSO (without screen and buttons) than to go for a stand alone DSO. I will use an older Laptop which nobody wants any more in the family. Windows XP is still good enough for the software that comes with an USB-DSO.

I hope that the discussion about oscilloscopes is still relevant to this Joule Thief forum? I guess it is, because we want to measure Joule Thieves?

Besides a scope, one more piece of equipment seems to be essential: I am talking about a "Bench Power Supply". It allows to accurately adjust the supply Voltage and the allowed Amperage (to protect your circuit) which is very helpful while testing a circuit. It can be a rather simple one.

A "bench power supply" and a DSO lift your experiments to an other level.

I got this power supply, and it helps a lot:

http://www.conrad.at/ce/de/product/511812/LINLABORNETZGERAeT-VLP-1303-PRO/SHOP_AREA_17452&promotionareaSearchDetail=005

Greetings, Conrad

[jadaro2600]

I've been away recently.

I apologize for the brevity in this post, but I'm looking for a JTC style circuit which produces AC in as clean a way as possible.  This means it should utilize two paths, or a center tapped transformer, this won't be a problem ...

Any suggestions would be appreciated.

- - - - - - - - -

On a side note, I recently pulled the driving board for a scanner bulb out along with the bulb itself - low an behold, it was a joule thief style circuit.

Pictures coming as soon as I dust and clean the house and get everything settled with this sinus infection ( cleaning hasn't helped, but there's literally a brooding hoard of dust bunnies and they're fixing to lay down fire if I don't engage in a preemptive attack ).

[Pirate88179]

jadaro:

Welcome back.

What do you mean by "clean" exactly?  A single frequency as opposed to multiple frequencies?  A good solid sine wave?

I am just curious.

Bill