Return-Path: Received: (qmail 17724 invoked from network); 13 Nov 2002 12:31:10 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 13 Nov 2002 12:31:09 -0000 X-Priority: 3 Received: (qmail 15461 invoked from network); 13 Nov 2002 12:30:39 -0000 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 13 Nov 2002 12:30:39 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18BweS-0005N9-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 13 Nov 2002 12:29:48 +0000 Received: from [134.58.10.57] (helo=mail3.cc.kuleuven.ac.be) by post.thorcom.com with esmtp (Exim 4.10) id 18BweS-0005N0-00 for rsgb_lf_group@blacksheep.org; Wed, 13 Nov 2002 12:29:48 +0000 Received: from dell-rik.fys.kuleuven.ac.be (pc-10-33-165-177.fys.kuleuven.ac.be [10.33.165.177]) by mail3.cc.kuleuven.ac.be (8.12.1/8.12.1) with ESMTP id gADCTHhh076858 for ; Wed, 13 Nov 2002 13:29:17 +0100 Message-ID: <5.1.0.14.0.20021113122956.02bb0e00@pb623250.kuleuven.be> X-Sender: pb623250@pb623250.kuleuven.be X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Wed, 13 Nov 2002 13:35:23 +0100 To: rsgb_lf_group@blacksheep.org From: "Rik Strobbe" In-reply-to: <19c.bc77907.2b016601@aol.com> MIME-Version: 1.0 Subject: LF: Tuesday's riddle (part 2) Content-Type: text/html; charset=windows-1252 X-Spam-Status: No, hits=0.0 required=5.0tests=IN_REP_TO,SPAM_PHRASE_02_03version=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Content-transfer-encoding: 8bit Hello Marcus,

very interesting.
I did the experiment with a BC547c and as Andy I got a negative voltage.
While playing with it I reduced the voltage to +/- 5V and saw an even more interesting effect, over a range of a few 10mV I got a nice sawtooth signal. I wonder if someone can reproduce it ...

73, Rik ON7YD

At 14:58 11/11/2002 -0500, you wrote:

Hi group,

this little experiment was pointed out to me by Ralph, DL2NDO a few years ago:

You need an ordinary NPN transistor (eg. 2N2222), a 9V battery, a 1k resistor and a voltmeter. Connect the negative battery terminal to the base and the positive to the emitter, via the resistor. Now predict the voltage drop between collector and base. Can't be too hard...

Then measure it - you'll be surprised. Any explanations? We finally ended up opening the poor transistor's case.

Have fun
Markus, DF6NM