MJLorton Solar Power and Electronic Measurement Equipment Forum
Older Technology => Older Technology => Topic started by: SeanB on February 04, 2013, 02:17:15 PM
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Thought I would share a few pics of my Wheatstone bridge.
Front panel.
(http://farm9.staticflickr.com/8235/8445608890_7ea986228f.jpg) (http://www.flickr.com/photos/33277124@N08/8445608890/)
Wheatstone bridge (http://www.flickr.com/photos/33277124@N08/8445608890/) by SeanB_ZA (http://www.flickr.com/people/33277124@N08/), on Flickr
Shortform instructions inside the lid.
(http://farm9.staticflickr.com/8355/8433224514_43a7e2b2f6.jpg) (http://www.flickr.com/photos/33277124@N08/8433224514/)
Inside front cover (http://www.flickr.com/photos/33277124@N08/8433224514/) by SeanB_ZA (http://www.flickr.com/people/33277124@N08/), on Flickr
Back cover removed, all metal screws into nice brass posts.
(http://farm9.staticflickr.com/8470/8432141291_843337bfb8.jpg) (http://www.flickr.com/photos/33277124@N08/8432141291/)
Inside view (http://www.flickr.com/photos/33277124@N08/8432141291/) by SeanB_ZA (http://www.flickr.com/people/33277124@N08/), on Flickr
Meter movement back with it's wirewound hand made resistors.
(http://farm9.staticflickr.com/8327/8432142985_28fd36aa12.jpg) (http://www.flickr.com/photos/33277124@N08/8432142985/)
Back of meter (http://www.flickr.com/photos/33277124@N08/8432142985/) by SeanB_ZA (http://www.flickr.com/people/33277124@N08/), on Flickr
Range resistors, they look like bamboo sticks.
(http://farm9.staticflickr.com/8189/8433230898_d2647c9da7.jpg) (http://www.flickr.com/photos/33277124@N08/8433230898/)
Range switch (http://www.flickr.com/photos/33277124@N08/8433230898/) by SeanB_ZA (http://www.flickr.com/people/33277124@N08/), on Flickr
Side view of the switch.
(http://farm9.staticflickr.com/8054/8432147471_b61bdd80f2.jpg) (http://www.flickr.com/photos/33277124@N08/8432147471/)
Switch details (http://www.flickr.com/photos/33277124@N08/8432147471/) by SeanB_ZA (http://www.flickr.com/people/33277124@N08/), on Flickr
Galvonometer showing the offset due to the shorting link.
(http://farm9.staticflickr.com/8086/8432151299_1f734fe3b8.jpg) (http://www.flickr.com/photos/33277124@N08/8432151299/)
Galvanometer (http://www.flickr.com/photos/33277124@N08/8432151299/) by SeanB_ZA (http://www.flickr.com/people/33277124@N08/), on Flickr
Hard to get a lower resistance shorting link than this copper foil across the inputs.
(http://farm9.staticflickr.com/8072/8432154619_9c43ed92cc.jpg) (http://www.flickr.com/photos/33277124@N08/8432154619/)
Close to zero (http://www.flickr.com/photos/33277124@N08/8432154619/) by SeanB_ZA (http://www.flickr.com/people/33277124@N08/), on Flickr
All running off 4.5V from 3 cells. The original D cells it had in it when i got it had leaked a little, and I did not have any to hand when I had finished cleaning up the holder and so I used 3 C cells and some metal spacers ( actually some vibration mounts) to fill the gap, along with some cardboard to fill the sides. Works well enough, and the cells are a lot cheaper to buy, and last just as long.
(http://farm9.staticflickr.com/8507/8433242148_679b44701d.jpg) (http://www.flickr.com/photos/33277124@N08/8433242148/)
batterybodge (http://www.flickr.com/photos/33277124@N08/8433242148/) by SeanB_ZA (http://www.flickr.com/people/33277124@N08/), on Flickr
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What a gem! I had not heard of Yokogawa before I came across a clamp meter of theirs I really want for review:
Yokogawa (CW10): http://tmi.yokogawa.com/products/portable-and-bench-instruments/portable-power-monitorrecorder/model-cw10-clamp-on-power-meter/
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Very neat inside and out! the blobs of solder on the "bamboo" range resistors, I guess they were for fine adjustment?
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Those are to solder on the leadout wires, as nichrome or manganin resistance wire is both very fine and a pain to solder, so it is likely this is a silver loaded solder to attach the copper leadout wires reliably.
I had a lot of roach droppings inside and out, and the case has been nibbled a bit by rats, though luckily only the leather strap and outer case had bites Took a week to clean it with a cloth and bag it with roach spray to kill those inside, and remove the egg cases.
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Brilliant , see how could anyone not want to own a piece of equipment this like, far better than all this soft touch backlit stuff, which I doubt would last the test of time, and I would bet this one would still be there doing its job well. Your duty bound to look after and use this piece of wonderful history.