--R. A. Leskovec January 30, 2001
There are some problems that can potentially severely limit the amount of working stations in the 308 lab and inconvenience yourself as well as everyone else.
Through carelessness and lack
of focus, the users cause fuses to be blown in the DMM's (Digital MultiMeters) and
in the Wave generator, which cannot
readily be replaced. This removes the
units from service until I am able to repair them. On the other hand, we have found, that once the situation is carefully
and clearly explained, the incidents go practically to zero! So
we appreciate everyone’s cooperation.
In the case of the
DMM's, please clearly understand the
difference between measuring voltage and current, so that you do not hook the
current function directly across a power source, as this will blow the
fuse. I can replace these with some
difficulty, but at least do not have to move the table, to remove the cable
that ties down all the equipment.
In the case of the HP33120
Function Generator, the problem is very serious because I have to completely
remove the unit, and take it to the shop to replace an internal fuse that is
soldered in! So please be cautious to
carefully check your circuits and NEVER connect a voltage source such that it
feeds back into the OUTPUT of the generator!
This includes power supplies as well as another generator, even if the subject generator is OFF!
Incidentally, scope probes
do not have any decent bandwidth in the x1 mode. They have more bandwidth in the x10 mode but need to be calibrated. The scopes have calibration signals on the front panels, which
also give you a way of checking that both the probe and scale factor of the
scope are correct. Calibration procedures
are explained on a large HP "poster" to the right of the chalk board
in the front of the room, and the little “tools” are in the stockroom tray.
If you suspect there is a
problem with your generator or DMM, the Lab Assistant in the stockroom has a
loose-leaf “Operations and Information
Manual” in which there are some troubleshooting sheets that may help you
diagnose the problem. There are also
some labels on the instruments themselves.
But if it things still don’t work, please send email including the table
number to:
help@eecs.cwru.edu