Anyone try this for a JT?

[Legalizeshemp420]

I think I found a pretty nice transistor for a JT but I am still new at this so you tell me if you have tried it or if it is pretty good for one based on its datasheet.

http://www.diodes.com/datasheets/ZTX1048A.pdf

[Pirate88179]

http://www.overunity.com/13175/25mv-joule-thief-powered-by-peltier-merely-using-our-body-heat-free-energy-247/msg350688/#msg350688

It was discussed a bit in this topic link above starting with the post in the link.

I have been playing with these of late:

http://www.mouser.com/search/ProductDetail.aspx?qs=4aVxpR%2fL9VKG%252bXivuPIp9Q%3d%3d&utm_source=findchips&utm_medium=aggregator&utm_campaign=512-FJD5553TM&utm_term=FJD5553

"Fairchild High Voltage Fast Switching Transistors  Fairchild's high voltage fast switching transistors are bipolar junction transistors that provide ultra-fast switching speeds and low saturation voltage. The FJD5555 offers saturation voltage as low as 0.5V and the FJD5553 as low as 0.23V. The energy-efficient transistors feature a high breakdown voltage of 1050V and are packed in space-conserving 64mm2 DPAK packaging. The devices are ideal for electronic ballast, power supply, and industrial designs."

If I can ever get my circuit to work I think these are the best I have seen so far.  Down to .23 volts operation (probably lower) and can handle high voltage.  It is the smd package but there are workarounds for that.  I am always in constant search for the "perfect" joule thief.  I have about 20 of the 5553's.

Bill

[Legalizeshemp420]

MAN OH MAN!!!

I don't do SMT so when you said there are workarounds for that my eyes grew large....HOW?  The only thing I saw was a way where they soldered a wire across the terminals and cut the wire between them but that doesn't help me.

I was reading this about the right transistors for the JT

The JT transistor must also have a low Vce(sat) (collector to emitter saturation voltage) at high currents. I look at the graph and see if the transistor's collector saturation voltage is 1/4 volt or less at currents of at least 250 mA, but hopefully at closer to a half amp.  The BC337 (Vishay) shows the Vce(sat) rising above 0.25V when the collector current gets up to more than a half amp.  Every BC337 that I have used can handle current better than a PN2222A or 2N4401, so I recommend it for JT use.  The same Motorola datasheet for the 2N3904 shows that the Vce(sat) rises above 0.25V when the collector current is about 75 mA, and at 200 mA it is over a half volt, and that is very bad, because it is wasted power heating the transistor and not lighting the LED.

That is from Acmefixer on his blog and the graph I was looking at on that SMT looked bad.  What did I overlook?

[TinselKoala]

You can get adapter boards for the devices, but mounting the device to the adapter board can be tricky, unless you use solder paste and hot air or an oven.
http://www.proto-advantage.com/store/index.php?cPath=2200&gclid=CJWSr-Gi97kCFepZ7AodVzwAiA
http://www.proto-advantage.com/store/icsoldering.php

[Pirate88179]

Well, you can see the transistor in the photo.  It just happened to line up with the copper ringed holes in this proto board.  Before I found this board, I simply soldered 22 ga. wire to each of the transistor terminals and then soldered that to an existing circuit board in place of a regular npn transitor.  Since my circuit does not work (yet) I can not offer anything about the performance of this transistor in a JT circuit.

I will keep everyone posted about this in the JT thread.

Bill