Hi everybody,
I own a 34461A since more than 1 month now. This is my first decent bench DMM. Hope than I will not become a volt nut !!!
I am ready to play that game, and already collected some data, but before posting them I would like to submit some observations (see graph below) I made 2 weeks ago.
Initially I wanted to know the warmup time of this DMM, but, when looking at the large drifts, I was a bit disapointed.
I suspected there was a relation between this drifts and the forced cooling system used on this DMM, and decided to log data with the DMM in normal "configuration", and also with the series of holes placed on both sides blocked whith a piece of paper and adhesive tape (but fan still running).
The results are shown on the graph below and pretty obvious.
Furthermore, I noticed that the temperature reported by the DMM is less (yes LESS), when the air entrance are blocked (-1.5 to -2 degrees Celsius)!!!
I repeated this test 3 times and there is absolutly no doubt about the results.
So, I am really wondering about this cooling design and it's effects.
If I am right, other DMMs like the 34401A do not have any forced colling system.
The 34460A do not have any fan. Is anybody there could do some data logging?
Same with the 34461A. I am curious to see the results of other users doing the same (with and without blocking the air entrance).
Anyway, you are the experts !!! I am looking for your comments.
It would be interesting to know how is measured the internal temperature, where is placed the sensor, etc ...
I am really curious to understand what is happening there.
In addition, a picture of the shunt that I am using.
Jean