New comer needs any and all help

[jhsmith87]

i dont know why it is dropping in voltage like that then, my only conclusion is that it is from the same reason i have been having problems with this whole time, some wires not making good contact. and i can no solder so it is really starting to bother me.
but as far as the transistor no i have been using a 2n3055 the other ones kept braking the "legs" off when i would try to twist wires to them. and as i said before my base resistor is a 1k variable i decided to go with that one so i could just turn the knob and see what happened. other than that though yea my turns are the same, and i am using a AA battery. and i am using a 200v 22uf cap. i think the problem is my wiring. i can not solder and in the end after i finish any project that is always the problem or the down fall of the project.
i have tried for a long long time, at least two years constantly working on trying to learn how, even paid a jewelry maker to try to teach me how. no luck, since my back injury my hands are just no steady enough. and no matter how hard i try i just cant do it.. hell its hard enough just to work with these small parts.

[truesearch]

@jhsmith87:


Sorry to hear about your difficulties with soldering. I can imagine the frustration and also the resulting inconsistent test results.


Have you tried using one of there devices? They will allow you to secure components and wires in-place. However, you will still need to run your soldering iron "by hand" to melt the parts together. . .
Link: [size=78%]http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_72865_-1[/size]


truesearch

[jhsmith87]

yea i have one of those.. still no good.

[TinselKoala]

Ah... I'm sorry to hear that, I was about to suggest the same thing. Harbor Freight has them for around 3 dollars, and I have two or three of them.

Yes, I agree that the problems are likely due to poor contact in the wiring. The lower your voltage, the more these little things work against you. Voltage is the ability to push current thru a resistance, so if your resistance is high and your voltage is low.... well, you don't get much action. And the operation of the JT circuit depends on oscillations, and if your contacts are "scratchy" all kinds of screwy things can happen to oscillators.

Soldering is definitely a skill that needs to be practiced, it needs a fairly steady hand and good vision. I usually use magnifiers when soldering, I use the "third hands" whenever convenient.... but being able to steady the hands is a real problem. You might be able to set up some kind of wrist rest that you can use together with the "third hands" and get steadier that way.

But in any case if you are careful with the  breadboards and don't force too large wires in there--- or the leads of a 2n3055!--- they should work OK with good enough contact.

A 1K base resistor, as I found out, isn't enough to get into the adjustment range we need; I just made a video showing some variations on this circuit we've been playing with, lighting up a bunch of LEDs and varying base resistance with a 10K trimpot.... for higher input voltages than 2 volts, a 50 k pot will be my next test.

http://www.youtube.com/watch?v=8X0oY_1UP3A

[truesearch]

I though too that "breadboarding" is about the only other option if soldering is out.


And like TinselKoala pointed out it is paramount that good (ie low resistant) connections are made. You'll find that true with connecting test equipment such as oscilloscopes too. Otherwise the observed results can be very random.


truesearch