YT2095

the idea is inefficient, rolling implies low friction, and you need friction to generate the charge. also, Electrons are Negatively charged, not positive

insufficient data in all aspects to provide a meaningful answer, please elaborate.

the D (like C and A) prefix is only part of it, try adding 2S in front of it and have a look. no promises, but in semiconductor nonmenclature it`s common to abreviate part numbers that way. edited to add: that if you find the 2SD718 (the C suffix is just the pin orientation), you May find that other Semi is a Complimentary Pair to it. I`ll have a look tomorrow for you when I have a bit more time. ========================================================================== meh, naff all on TV, so here you go dude: http://www.datasheetcatalog.org/datasheet/WINGS/2SD718.pdf and as I suspected, it`s compliment transistor IS the other number you mentioned. http://www.datasheetcatalog.org/datasheet/WINGS/2SB688.pdf good luck with your project

put DC into a transformer and it`ll stick (I tested that one that too). it Would be interesting to see what would happen at a lower frequency and maybe not use a sinewave but rather a square wave? I also expect that it may be possible to use a regular relay AC driven, if you use matched capacitors. although it would probably only work well at a given frequency.

no one`s saying AC relays aren`t available, these are specially designed for the job and can`t be substituted with a regular relay without support circuitry (such as a diode). btw, I tested your idea before I posted #4, and I assure you again, it doesn`t work, I used a 9 and 6v type, nada.

the above doesn`t work, you need at least 1 diode (half wave) for it to work. try stick a paperclip to transformer

can`t you rectify the 9VAC to make DC instead? there`s not much in the way of "Electronics" that works on AC, it tends to prefer DC, a fullwave bridge rectifier feeding a relay will work.

if you only need a small amount, strip down a few dead Zinc Carbon batteries, it`s a bit messy but it`s Free and as a Bonus offer, you get a free Carbon electrode with each one!

indeed, Happily that info comes with each pack of Photopaper that you buy and also some films, or at least it does with Ilford paper. it helps when I`m doing long exposure Night time shots that require exposures of 10 seconds or more (sometimes Minutes), however this would be a whole lot easier to calculate if my working out (as posted in this thread) can be verified as correct or not. Done

and 35mm film canisters can be used to mate a compact cameras lens to a telescope eyepiece too (I love Ghetto-Tech) speaking of which, I just took some pictures of a pair of pinhole cams that I made, the 1`st one is the one I described with the pringles tube, it shows an example of the brass shim with a needle in it (bottom left), the Business end of the pringles cam (top left), the end cap with the Blue-tack to hold the film/paper in place (top right) and an example of a slightly underexposed paper negative that I took with the cam (bottom right), you can clearly see the blinds and the roof tops outline with some trees sticking up: This pinhole cam is the 1`st one I ever made almost exactly a year ago, the principal is exactly the same and you should be able to see some light coming through the actual pinhole itself (I bounced the flash), inside the cam is the 1`st ever picture I took with it (just to show where it was placed and how it fits inside), and resting up against the cam is a Positive I made from that negative, and yes the window was dirty with Crayon and chocolate hand prints! (ya gotta love kids), this is what it looked like from my Daughters room that morning:

yup perfectly... "The f-number of the camera may be calculated by dividing the distance from the pinhole to the imaging plane (the focal length) by the diameter of the pinhole. For example, a camera with a 0.02 inch (0.5 mm) diameter pinhole, and a 2 inch (50 mm) focal length would have an f-number of 2/0.02 (50/0.5), or 100 (f/100 in conventional notation)." taken from: http://en.wikipedia.org/wiki/Pinhole_camera#Calculating_the_f-number_.26_required_exposure

there is no "internal optics" at all, anywhere, I made this camera myself. and although I`m quite willing to explain how (later), it`s not required to work out the correct progression for the shutter speed. if we take the sunny 16 rule of perfect exposure, we have f16 @ 1/125s for ISO 100. and as you know, for each f-stop you move, you either have to Double or half the shutter speed depending on which way you move the stop. so f16 @ 1/125 sec is equal in light to f22 @ .25 sec and so on. now using my f-number sequence I derived, and starting at f8 @ 1/125sec, when you get down to f512 will the time be 512 secs? And is my f-number sequence correct? =============================================================================================== as promised, the details of what I did are here: http://www.scienceforums.net/forum/showthread.php?p=451785#post451785

here`s how: you`ll need an empty Pringles tube, clear out the little bits you missed when you were eating them, and then cut a 1x1cm hole in the middle of the metal based (I used a Dremel). then you need a can of Matt Black spray paint to paint the inside of the tube (it prevents unwanted internal reflections later). while this is drying ( a good 12+ hours is best) you need to get some brass shim stock about 1 inch square and Flat, if you can`t get any of this then CAREFULLY cut the side out of an Aluminium soda/beer Can, this will work just as well. next you need a sewing needle, I used one that was .5mm wide at it`s widest, although for the 23cm length of the tube, 0.7mm is the optimum width. then you need to place your metal plate onto some soft wood, place the needle point in the center of this and gently tap the needle through the metal. use some sand paper to go over the hole to make sure it`s all smoothed down again with no bulge in it, then insert the needle again so that it passes cleanly through (it can sometimes clog back up a little after sanding). so now you have a thin metal plate with a very tiny hole through the middle of it and a tube that is painted Matt black inside. get a black marker pen and color the one side of your metal plate, place this colored side nearest the tubes metal base (that you cut the hole in) and position it so your pinhole is central to the tubes base, and then tape it into place. so Now you have a tube with a very tiny hole in the one end that lets in a very small amount of light, this should be the Only place light gets into the tube! (other than the end you`r looking into). now we deal with the end cap, that clear plastic cap that seals the tube to keep your Pringles fresh. you need to make That light-tight also, sadly spray paint doesn`t stick to it very well and will peel off and flake easily, so you need to use black card to block most of the light and electrical tape or Aluminium exhaust tape (that`s what I used) yo seal the remaining light leaks. cut the black card to shape to fit inside the cap and glue it in place, do the same for the outside as well and then go around the rim with your tape. when in place you should now have a tube that`s entirely blacked out inside with only a tiny pinhole to allow light in. take the end cap off, and stick a small piece of photographic film or paper to it so that it`s central and doesn`t prevent you putting the cap back on (leave a a good 5mm border), I used blue-tack on the back of my film to secure it in place, all this MUST be done in either total darkness or with a safe-light on (I load mine up in the darkroom). Now you have a working and Loaded camera! with your finger (or some electrical tape) over the pinhole, you can now walk out into the light again. place your camera in a position where it won`t get disturbed or the scene blocked that you wish to photography, free of vibration too, and then remove the tape (or your finger) and note the time. I find that 30mins works quite well for a range of film or papers when taking outside pictures through a window, of course you will have to experiment yourself which is the best exposure time. if the negative is too black/dark then use less time, if there`s little detail and it`s mostly clear then use a longer time. this is the Bare-Bones-Basics of a pinhole camera (Camera Obscura). there`s no real restriction of what size of Tube or Box you make one out of either, the only Real criterion is that box be light-tight and the pinhole (as the name suggests) not be Too big. yes you can even black out a window in a room with some cardboard that has a hole in it, and use a sheet of film the size of the opposing wall! if you wanted to Have Fun!

most peoples bodies "Jolt" upon falling asleep, sometimes the brain isn`t quite asleep enough not to notice this and so it startles you a bit. it`s quite normal though. it Might be an idea to set up a Voice activated tape recorder in the room just to make sure there isn`t some sudden Sound occurring that`s waking you up before you have chance to recognise it as well.

some lamp shades have a wire clip that clips directly to the lightbulb.

well, according to the formula that I looked up, the maths that I derived f460 from is accurate. and an online calculator that I used supports my number progression, but not as high up as I need to go if it`s of any use to you in assisting me, the number progression I assumed is: 8,11,16,22,32,45,64,90,128,180,256,360,512,720,1024,1440,2048. I have verification that it`s accurate up until 90, I had to assume the rest myself. and I assure you, it requires no lens or focusing mechanism, a pinhole camera is quite efficient for it`s simplicity.

the f Number is 460. as I mentioned Focal length times Aperture (230mm x 0.5mm in my case). what I`m trying to work out is the exposure time, and according to my calcs it should be ~16 mins using ISO 100. oh yeah, and there is No lens, it`s a pinhole camera.

they`d be hard pushed to ruin it as badly as the most recent version of "War of the Worlds", that well and Truly Sucked!

yup, f/8 (often in italics too). my calculations So far, based on a 0.5mm aperture and a focal length of 230mm, gives an f-number of 460. so what I`v done is look at the pattern in the number progression of f numbers and continued it onwards to f 2048. I did the same with a variation on the "sunny 16" rule" using ISO 100 at 1/125 sec but using f/8 rather than 16 (it was a bit overcast that day). so, cutting it short, in the columns as the f-number got smaller I doubled the time to keep the total light the same. I noticed that f/512 was the closest to my f/460 And that the time in seconds was also 512. so in effect I just need someone (better at maths than me) to verify that my working out is correct.

yes sir.

sounds like you`r pulling from Cache mem, clear it and try again, it may involve deleting cookies too.

just a quick question, can anyone corroborate that 512 seconds at f512 is the equiv of 1/125 Sec at f8 (assuming that ISO 100 is used for both)?

Once

and Atoms are made of...?

can you provide ANY evidence to support this? in particular why a "Basic" soln is Safe? personally I`d fancy my chances in HCl rather than NaOH, but that`s just personal preference