In this video I show off one of my prized artifacts - a mid-20th century reproduction of the first piece of bench gear made - the Mirror Galvanometer! This was the must-have kit for the mid-19th century laboratory, and having a way of measuring minute currents at a time before signal amplification meant that every micro-amp saved was precious. Enjoy!
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Join Team FranLab!!!! Become a patron and help support my YouTube Channel on Patreon: http://www.patreon.com/frantone
- Music by Fran Blanche -
Frantone on Facebook - https://www.facebook.com/frantone/
Fran on Twitter - https://twitter.com/contourcorsets
Fran's Science Blog - http://www.frantone.com/designwritings/design_writings.html
FranArt Website - http://www.contourcorsets.com
How am I? Well I'm just recovering from a root canal and new zirconia crowns. I've been hurting far too much to make much plarn.
Vintage technology
How does the fine zero adjusting work?
Crafty device.
Very few responses from Fran.
Great instrument!,CDRX is Critical Damping shunt Resistor (X value is determined for adjust the total parallel resistance across the the moving coil and CDRX) This résistance is extremely accurate! Regards to France!
Hola !! Muy bueno. Me gustaria saber que tipo de alambre ocupa para, sostener la espira y lograr el momento torsor? Que diametro tiene 0,8mm. Saludos desde Argentina
thanks Fran great explanation
Why you are interested about how I'm? You don't even know me.
A thing of beauty is a joy forever 😎👍👍 thank you Fran
The mirror does even have to move only 4.5 degrees to cause that total deflection of 9 degrees
Not only that, but these type of galvanometers have the weirdest shape of tension wires… If you manage to get your hands on these torsion-tension wires and you put it under a microscope, you will see that they are thicker on the edges and thinner on the middle. This probably has a few reasons such as to prevent their spontaneous break (suppose small cracks might form along the cut edges so instead they made them thicker from the sides) and also to help the twisting behaviour take a uniform manner. These wires are usually are defined by their counter force at 100mm length and 90 degree torsion. I have a few of them and theirs is 0.2grams at 100mm length at 90 degree angle.
You also cannot just solder them with ordinary soldering material or ordinary soldering iron. For example the which I own need 130°C(266°F) soldering temperature. With a solder consisting of Sn-50%, Pb-30%, Cd-20%. Yea nasty material… So if anyone comes across such a device, be on the lookout and don't solder it with ordinary soldering iron. Cadmium is a nasty material.
Also the torsion wires can be made of platinum or Copper-Beryllium alloy. Latter is a nasty material as well.
Clever stuff, nice break down of that engineering marvel of its time.
Thank you. Love the galvanometer testing and how sensitive it is. I didn't understand the reason for the mirrors until you explained their use in increasing the width of the full range. Even followed the math to see how it worked…. Awesome!
I just found two of the GE galvanometers and I am wondering if I can use them for the galvanic skin response meter
Thank you Fran