Subject: More Java suggestions Date: Tue, 14 Sep 1999 14:38:08 +0100 From: Jeff Forssell <> To: "''" <> CC: Claes Ahlin <> Back in school after a tough summer. My 81 year old mother was visiting from USA and fell down a stairs and needed help for the 2 months she was here. Bad luck! Didn't get much done this summer. But the weather was nice at least. Hope you´ve had a good summer. I was checking to see if you multimeter aplet could be used to see in what situations it would be incorrect (parallell with a LARGE resistance) but it didn't take that into consideration- it gave the same reading at 2000 kohm as 10ohm. See the accompanying picture. While I´m at it heres the interpreter for Q basic in case you want to try the files I sent before. I've been looking at Walter Fendts Javas. some are quite illustrative. One that wasn't was about the "radioactive decay series". Do you have anything planned there? I'd like to find an alternating current aplet that would show the charge acculation resp magnetic field buildup graphically. I sometime try to show my pupils a water -electricity anology where pressure=voltage liter/sek=A pump=voltage spource small or clogged pipe=resistance double chamber with elastic membrane=capacitor turbine with inertial load=inductance That might be something that could make an interesting Java aplet I put together a very rough sketch of the C-L anology: Jeff Forssell personal homepage: my village technology homepage: Swedish National Institute for Distance Education (SSVH) Box 3024 SE-871 03 Härnösand /Sweden tel +46(0)611-55 79 48 fax +46(0)611-55 79 80 schools homepage -------------------------------------------------------------------------------- Subject: SV: re send multimeter plus more ideas Date: Thu, 16 Sep 1999 12:40:29 +0100 From: Jeff Forssell <> To: "''" <> Thank you! The aplet seems to work very well. Some minor problem and a couple of wishes: 1) if I change the range while the meter is connected, the measured voltage is not updated. (Hmm I tried it again and now it works. But if I reload the page and turn "ON" directly it reads 4,67V on 10 V range. If I change to 50 V range,4,76V stays in stead of 4,95V The Equivalent circuit is updated directly.) 2) I would prefer a much faster component value change while continuously pressing mouse <0.1s per change. One can always "fine tune" with single klicks. 3) I would like a possibility of writing in R2 values also. (4) Fu Hwang 1999 in lower left, in stead of 1998) -------------------------------------------------------------------------------- Subject: SV: SV: re send multimeter plus more ideas Date: Fri, 17 Sep 1999 07:46:05 +0100 From: Jeff Forssell <> To: "''" <> CC: Claes Ahlin <> Thank you! I still have the problem with voltage update on changing range even on the new aplet (i've tried in both NS 4.5 and IE 3.0). with a newly opened page: press ON V= 4,76V 10 range change to 50 V V still 4,76 (equivalent circuit Rs update properly) change to 10 V v changes to 4,95 change to 50 V changes to 4,76 The write in window for the values works well. I would (on behalf of Sweden and some other countries) like even comma "," to be interpreted as a decimal sign. Other clarity wishes: prefix the box with "R2" when updating R2 and suffix the box with "kohm" when R values being set. V [ ] R [ ]kohm R2[ ]kohm I think the current circuit would be easier to see if you had a wire connecting rather than 2 ground symbols. When the Rm box is not checked, it would be good for the Eqivalent circuit to be altered perhaps like this: Hope you don't think I'm complaining! I use your aplets a lot! I wish someone would go through my stuff to help me develop it! -------------------------------------------------------------------------------- Subject: Very Nice ..... but....more ideas Date: Sat, 18 Sep 1999 22:12:40 +0100 From: Jeff Forssell <> To: "''" <> Very nice! But I still get the update problem when changing range (both IE 3.0 & Nets 4.5). Have you tried as the FIRST step after opening the page? I know that the problem goes away if I do a bunch of other stuff (change values I think). One other problem: I think that the multimeters that I´ve used have had the red lead positive when in the resistance mode (which makes it easier to interpret when measuring on active components like diodes). I havesn't checked that in reality since I had the thought though. Reviewing my own work: I'm mainly interested in getting my web resources polished up for my Swedish students which mean that it is in Swedish which makes it difficult for non Swedes to say much about it.