Help idnentifying some sort of resistenc box? - Page 1
Forum section: electronics / projects

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 08:55:01 am
content: So i got this coupl of days agoand as u can see it looks like a R boxbut i dont have a clue how to operateit.Its from the 60s so its pretty old butinside its like new and to get thing more harderevrything is chines evrything.Hope somone can help.Ps:Sry i cant seem to upload anything to this forum cuz the photos are high res.I used g+ for the photos sry.https://plus.google.com/+EIsad/posts/SjRMDYQpZEw?pid=6147163271811628834&oid=113769772046139607620

author: JBaughb
author_rank: Regular Contributor
timestamp: May 10, 2015, 09:02:23 am
content: It looks like a voltage divider, but Im far from an expert.

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 10, 2015, 09:07:20 am
content: since it has a battery and an indicator it must be a bridge to precisely measure resistors, see Wheatstone bridge.

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 09:20:32 am
content: Quote from: PA0PBZ on May 10, 2015, 09:07:20 amOh that kinda look like that i even found some other equpment looking nearly like this oneprobably will have a play with that when i have decoded the chines.

author: technix
author_rank: Super Contributor
timestamp: May 10, 2015, 09:35:51 am
content: This is a Model QJ-20T Cable Tester by Shanghai Lianyan Electric Test Equipment Works, manufactured December 1963. Does this 51-year-old but of kit still work? Is it older than you?I will translate the rest of this plate (which have pretty much all its manual on it, with schematics) later.

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 10:03:28 am
content: Quote from: technix on May 10, 2015, 09:35:51 amIts older then my father i ma ony 17 lol.Idk if it works but it looks good from the insideidk how to test it.I am still learning.I would love to know how to test it .

author: technix
author_rank: Super Contributor
timestamp: May 10, 2015, 10:32:37 am
content: Quote from: Isad on May 10, 2015, 10:03:28 amWelcome to EE!Just don't get knee-deep in those test equipments and become what they call a volt nut

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 10:55:31 am
content: Quote from: technix on May 10, 2015, 10:32:37 amNah i hope i dont get that deep lol.Btw i dont have any usage for that so it might sit in the shelf for long time.but still would love to test it.

author: calexanian
author_rank: Super Contributor
timestamp: May 10, 2015, 05:43:35 pm
content: Thats a nice looking piece. Its a copy of an American design, that in turn was a copy of an older design. It works on the same principal as an Ohmite Ohm Ranger. just with dials rather than individual switches. I still use an Ohm Ranger regularly and I believe they still make them for ridiculous prices.

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 06:21:22 pm
content: Quote from: calexanian on May 10, 2015, 05:43:35 pmYeah but it isnt a resitenc box.Technix said it was a cable tester and as i dont know any chines ibealive that.

author: technix
author_rank: Super Contributor
timestamp: May 10, 2015, 08:12:54 pm
content: Quote from: Isad on May 10, 2015, 06:21:22 pmRead the label again, a little bit difficult to translate due to obscure jargons, but it does work as a resistor bridge at its core. If @calexanian can provide more info on that device I may tell you if they works the same.

author: Isad
author_rank: Frequent Contributor
timestamp: May 10, 2015, 08:32:10 pm
content: Quote from: technix on May 10, 2015, 08:12:54 pmOk that might have sounded totally dumb what i said to @calexanian.Sry but English isnt my 1 language.

author: calexanian
author_rank: Super Contributor
timestamp: May 13, 2015, 10:25:29 pm
content: Let me use this as a referencehttp://www.ohmite.com/cat/controls_ranger.pdf/url] (BTW the hypertext link on my compy is not coming up right. Sorry if you have to cut and paste)The unit at the top is a true decade box that selects the resistance by using 9 resistors and a pass through on 10 position rotary switches for how ever many digits you need. The second box utilizes just 4 resistors which can be added up in series to create decimal values of 0 to 10 thereby allowing the use of less resistors and more simple switches this Japanese unit is essentially a hybrid where you only have so many resistors, but have single knob per decimal place selection.

author: barry14
author_rank: Regular Contributor
timestamp: May 14, 2015, 01:23:21 am
content: What you have is a basic Wheatstone bridge for measuring resistors. It requires a battery to operate. One dial selects the range and the 4 decade dials determine the exact resistance. It includes a galvanometer for sensing bridge balance. It can also be connected as a Murray loop or Varley loop tester which were used years ago to locate faults in long telephone and telegraph cables. That's why the selector switch is labeled as it is: R for resistance, M for Murray and V for Varley.

author: calexanian
author_rank: Super Contributor
timestamp: May 14, 2015, 06:01:21 pm
content: Nice catch there. I did not look closely enough at the schematic.

author: Isad
author_rank: Frequent Contributor
timestamp: May 14, 2015, 06:32:49 pm
content: Seems like a nice bit of gear only problem i dont have a usefor this.A friend gave me this he told me take what uwant and i simply just got this cuz i thought it was gona be aresistenc box well this is gona si in the shelf for a long time.Thanks you all for helping.