Potentiometer and transistor question

I can't seem to find the values for a potentiometer I am hoping to use. Well I found what I think is the value @ https://www.symmetron.ru/suppliers/murata/trimmerres/r50e12.pdf but I'm not sure if it is correct for this particular one as the last marking isn't available. The pot reads J then a circle with a lightening bolt or similar then 102r. I'm hoping its a 1k pot but I'm not real sure. Also, I was wondering if there is a good substitute for a 2n3904 transistor. I'm scrapping these parts from old electronics and am not having luck finding what I need. Supposedly 1k resistors and the 2n3904 trans. are supposed to be common but I've yet to find them in any of the things I have parted out. Also, I need to know how to wire the potentiometer, specifically which is the ground. Any help would be appreciated, thanks.

102r means 1K to me.

For 2N3904:
https://alltransistors.com/transistor.php?transistor=3746
Then look on this webpage the line "2N3904 Equivalent Transistors" (after the transistor characteristics list)
The follwing page will give 58 entries

Added:
And I guess BC546 and 2N2222 could do the same job as already pointed out.

Kerim

What do you want to use the parts for? In a lot of applications, almost any small signal transistor can be used. It's quite likely that you could substitute the 2N3904 with something else e.g. BC547 or 2N2222.

How you wire the potentiometer depends on what you want to use it for. I would guess that the two connections next to each other are the ends of the track, and the connection on the other side is the wiper. "102" sounds to me like 1K. Don't you have a multimeter to check it?

thank you KerimF

---------- Post added at 16:39 ---------- Previous post was at 16:36 ----------

I'm trying to build a joule thief. I have limited parts and at the moment I don't have access to my multimeter as it is in storage. I'm new to electronics and just trying to get acquainted with it all. I am working on building a solar phone charger using outdoor solar lights for the panels. I am going to use the joule thief to step up the voltage then use another potentiometer to dial in the voltage at the end so I can use it for other applications as well.

I guess your input voltage is rather low (around 0.5V) unless you can add more cells in series.
Sorry if I misunderstood your project.

I have four cells in total, I'm using two for a phone charger, I plan to use the other two to build a solar camp radio. I also make my own home-made water rechargeable batteries that only put out about .5-.6v that I will be using at dark so I will have them on a quick change set-up. I think the solar cells are around 1.5v.

With 1.5V, things become easier. Good luck