Hi, great information. is it possible to convert this schematic to measure the resistivity of a semiconductor. I suppose a 4 wire jandel probe as input
It will need some additional programmability of the current and understanding of non-ohmic contact effects. possible adjustment of gain depending on the substrate resistivity. a bit out of scope for this particular design. thanks for the comments.
I have tried the 4-wire Agilent 34401A measurements. It's reasonably accurate. Mine is a dedicated sub ohm meter and it has more resolution (and it is very portable).
I would not play with the math on my bench meter (which is 34411,by the way). I would just use the 4-wire method. If there is some problem with that, I would get that fixed. Both your and my meters are recent models and spare parts should be still easily available. In fact, I bought my meter as factory refurbished.
![Yet another homemade milliohm meter (auto-zeroing)! [part 4]](http://i.ytimg.com/vi/2H-ueyYq98U/mqdefault.jpg)
![Yet another homemade milliohm meter (auto-zeroing)! [part 4]](/img/tr.png)
![Yet another homemade milliohm meter (auto-zeroing)! [part 1]](/img/n.gif)
Great job, man! I've just watched your 3 videos for the miliohm meter project! Thanks for the very useful information (especially about OpAmps)! :)
Hi, great information. is it possible to convert this schematic to measure the resistivity of a semiconductor. I suppose a 4 wire jandel probe as input
It will need some additional programmability of the current and understanding of non-ohmic contact effects. possible adjustment of gain depending on the substrate resistivity. a bit out of scope for this particular design. thanks for the comments.
Why not just use the Agilent 34401A meter? It has milliohms (4 wire)
I have tried the 4-wire Agilent 34401A measurements. It's reasonably accurate. Mine is a dedicated sub ohm meter and it has more resolution (and it is very portable).
I would not play with the math on my bench meter (which is 34411,by the way). I would just use the 4-wire method. If there is some problem with that, I would get that fixed. Both your and my meters are recent models and spare parts should be still easily available. In fact, I bought my meter as factory refurbished.