What are these few devices? - Page 1
Forum section: electronics / beginners

author: dzarren
author_rank: Contributor
timestamp: December 04, 2017, 03:09:43 pm
content: I have found a few devices that are quite old. Would you guys be able to help me out as to figuring out what they are and what they can be used for?The first one is strange, I have two similar ones. There's some stuff hanging on a wire on the inside, and it has a bubble level to ensure it is level with earth. I think it may be a galvanometer?This next one is big. I think it's some sort of device that tests your components and measures the values?And this is the last one, it appears to be some sort of resistance box? It is totally full of coils.It would be awesome if you knew what these things were and what I could do with them, and what they did in the past!Thanks!

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 04, 2017, 05:56:09 pm
content: A bit of googling confirms that your first device is a galvanometer. The second is an old school, less capable, version of the $20 dollar LCR tester. Some of the confusion comes from the selector for test frequencies - labeled with the old abbreviation Mc instead of the current MHz. Some googling is likely to land you an operating manual for this. The third appears to be a standard impedance chain. You should be able to tell quickly if it is capacitance, resistance or inductance. I am assuming that the "knobs" are actually shorting plugs which bypass the adjacent value.

author: chris_leyson
author_rank: Super Contributor
timestamp: December 04, 2017, 06:16:00 pm
content: Nice find, the first instrument is definately a galvo as it's got the spirit bubble for leveling. The GR 821 old school impedance bridge is probably still useful today, they were very well built. Manual herehttp://www.ietlabs.com/pdf/Manuals/GR/821-A%20Twin-T%20Ckt.pdfNot sure about the last one. But there is still a small market for these things.

author: iainwhite
author_rank: Unknown
timestamp: December 04, 2017, 07:00:34 pm
content: This site is worth a look too:The General Radio Impedance Bridge Page

author: Gyro
author_rank: Super Contributor
timestamp: December 04, 2017, 08:32:21 pm
content: You seem to have got quite a little pile thereIt looks as if you have two mirror galvanometers (I can see the edge of the second one alongside it). You've probably guessed but these were used with a fixed light source and a separate scale - the light reflects off the mirror and back onto a scale (usually about 1m away) acting as a long weighless pointer.The impedance bridge has already been covered. It looks to work over a decent frequency range.Yes, the third item is a resistance box (a capacitance box would have elements in parallel, not series). Removing the plugs puts the indicated resistance value into circuit.Looking further down your pile... Underneath the resistance box is a PYE self-contained light spot galvanometer (lamp and scale built in). That speaker has clearly had it but has a probably useful magnet in it. It has a pressed sheet metal chassis so probably wasn't anything special. The black box on the wooden base between the speaker and PC PSU could be a current transfomer (there looks to be a hole for a primary lead through the middle but it's hard to see, it might be something more interesting). I can't see enough to make sense of the light wood box at the bottom left of the last photo.

author: Cyberdragon
author_rank: Super Contributor
timestamp: December 05, 2017, 03:41:44 am
content: QuoteI think it is something more interesting. It seems to read *something* "cell" which could be "standard cell". If it's not a brand name, it's a calibrated battery, not a transformer. It was probably used to power the galvanometer for experiments (it says "physics laboratory" on the label). Warning, they are fragile and contain glass vials of liquids! Test it with a multimeter.(Queue the pitch) For more information on galvanometers and standard cells, see the Meterology section of this forum.edit while posting: Don't leave the battery on it's side, they like to be kept upright so the liquids settle properly!

author: dzarren
author_rank: Contributor
timestamp: December 05, 2017, 04:55:21 am
content: Yes that thing is a standard cell. I think its 1V. I didnt keep that one there you see in the picture, but I did keep this one here. Mostly because of the dates on it, appears to be from great antiquityAnd this here I took home, I wasnt sure what it was, but I knew it was really old, and i really really liked the look of it. It was "clean" when i brought it home, but the next day, I noticed what appeared to be condensation on top. I touched it, and it was not condensation as it was somewhat sticky. I didnt think much of it and left it for a week or so. I came back and noticed it seemed to have even more "condensation" on it. I got to cleaning it off with water, and then later with IPA. The "condensation" was brown and had a decent funk to it. I was really curious as to what this box was, so i unscrewed the fasteners that appeared to be pinning down the top panel. As i lifted the top panel, it didnt want to budge at first, but when i got it off, there were all sorts of components on the underside, but the entire thing was filled TO THE BRIM with some horrible brown somewhat viscous fluid. It was absolutely terrifying. I thank each and all higher powers that I didnt spill anything, but that was just horrific. I noticed my throat started to hurt from breathing whatever vapours this thing was exuding, I put the top panel back on as quickly and carefully as i could, and fastened the panel back down, tightly. I actually ended up breaking a flathead bit cus i was reaming it down with the drill so fast. I needed to escape that as fast as possible. I was able to dispose of it in a proper electronics disposal. What was that thing? What is this so called Volt Box? I thought it looked beautiful, but god, that smell. That thing could not have been healthy to keep around. I did keep the badge though.Is it also some sort of standard cell? it goes all the way up to 750 volts. There was no detectable voltage between any of the leads.

author: Cyberdragon
author_rank: Super Contributor
timestamp: December 05, 2017, 06:49:54 am
content: That's patented 1899, it was probably made some time later.That was high voltage insulating oil, it may have been toxic. You still could have kept it if you drained it, washed it, and refilled it with modern mineral oil. As for the device itself, it appears to be a variable voltage divider or something.EDIT: I've just found the instruction and lab book for the entire system. E.M.F. means electromotive force, IE voltage, these machines, when put together, form a big voltmeter of extreme precision.https://books.google.com/books?id=jhrOAAAAMAAJ&pg=PA70&lpg=PA70&dq=weston+volt+box+model+175&source=bl&ots=XpUo9nYR0U&sig=-4JNj0eQFIqFeFAe1wBPZsyeGbw&hl=en&sa=X&ved=0ahUKEwiQmZicn_LXAhWBUN8KHV-_BokQ6AEIJDAA#v=onepage&q=weston%20volt%20box%20model%20175&f=falseEDIT: It was PCB, and was poisonous! I hope you disposed of it in hazardous waste properly! Shame really to dump what seems to be an incredibly rare device, but better safe then sorry I guess.

author: CJay
author_rank: Super Contributor
timestamp: December 05, 2017, 12:39:10 pm
content: PCB in this instance being Polychlorinated Biphenyl and it's incredibly unpleasant stuff that has to be disposed of in a furnace that's hot enough to completely destroy it (>1000C)or it just becomes even more toxic.I would be somewhat worried that I'd been contaminated if I had manually cleaned that stuff uphttps://en.wikipedia.org/wiki/Polychlorinated_biphenyl