What type of transistor is Q1?in the link below.


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Thanks to Astroboy907 and Lemonie, the page dealing with the original link has been traced: http://home.comcast.net/~ddenhardt201263/desulfator/lowpower.htm.

These low power desulofators deal with FETs, both N and P channel. A MOSFET would be perfectly fine here, but we still don't know the channel type or whether it is depletion mode or enhancement mode. In order to tell the difference, look at the schematic by Ron Ingraham, directly above the dreaded Don Denhardt schematic. See the MOSFET there? The arrow pointing "in" denotes an "N Channel", while an arrow pointing "out" would be a "P Channel". See the bar directly above the arrow? It is solid which means it is a "Depletion mode" while a dotted line (three lines, one above each of the "legs") means it would be an "Enhancement mode". So, Ron's schematic uses a "N Channel Depletion mode" MOSFET. The one you show us, Don's, is anyone's guess, although I would say it is at least depletion mode. If you have SPICE software. throw it together and see what'll work. Or, if you have both N and P types, build it and see which one does the job and which one fries (do so safely outdoors with a long enough wire on the power switch to get you away from it).

jbaker22 (author)  Quercus austrina6 years ago
So it is an NPN transister?
NPN (and PNP) denotes a bipolar transistor. N channel (and P channel) denotes some sort of FET (Field Effect Transistor) There is a difference between the 2. Check out Wikipedia for quick definitions. In this case, it is most likely (because we don't have a complete drawing of the part or a part number) a N channel Depletion mode MOSFET, in keeping with the other schematics around it.

This is just an educated guess - what you do with it is up to you, I accept NO responsibilty for any damage to life, limb or property as it is not my design and the design is incomplete.

My advice, try another design that is complete and lists all the parts.

iceng6 years ago
astroboy907 has provided the only circuit I was able to actually see.

Q1 the only transistor, is a badly drawn N channel MOSFET.

lemonie6 years ago
Why have you only posted the link to that image, rather than the link to the page it came from that tells you what parts are used?
e.g. like this: http://home.comcast.net/~ddenhardt201263/desulfator/desulf.htm

This is, unfortunately, a poor drawing. The transistor top is a depletion mode FET while the bottom is either a JFET or UniJunction transistor. I do not know what the artist wanted to draw.

canucksgirl6 years ago
Can you edit your question and use the link symbol (looks like a globe and a chain link) in the editor for your link?

We can't see the whole address because of it's length (part of it disappears on the right) and therefore we can't actually go to the address and see what your asking about.

I think these are the links relevant to this question:

The literal question mark, ?,  Astroboy was including in that last link might be screwing things up.
Here- I did it for you :)


irst of all << bug in commenting (making next typed letter part of link)

and second I think it is a type of FET- but I cant tell and my transistor schematic symbols are a bit fuzzy :)
This link to this picture "556alternate.gif", makes a lot more sense when viewed in context with the html pages and other circuit diagram pictures that go with it.

I think if you read this page:

Then look at the first diagram it links to, here:

In that image, "n_channel_schem.gif", the transistor is labeled as IRFZ44V, which is an N-channel enhancement mode mosfet. All the other parts are labeled too, which is nice.

Because the image you point to is mentioned second, and described as "alternate", and because its output stage, i.e. the two inductors, a mosfet, a diode and a capacitor, because those look to be the same... I am going to assume that the those parts are the same as those in the first circuit diagram, "556alternate.gif"

By the way, alldatasheet.com can help you look up the specs/pinouts for those parts you are unfamiliar with, e.g.

Also, thank you for mentioning this.  Just today I was trying to think if there was somewhere that had a good "desulfonator" circuit. I have heard the legends, yet I have not yet seen, or tried such electronic voodoo.  I've got a couple of bricked, sealed lead-acid batteries here, that do not seem to take a charge anymore.  I mean the open circuit voltage will climb to like 13 volts or so when connected to a charger, but they just don't seem to take, or deliver, significant amounts of current  anymore.  Perhaps one of these magic circuits could help? Anyway, thanks.