Received: from PCH.mit.edu (18.7.21.50) by mail.efplus.com (192.168.0.8) with Microsoft SMTP Server (TLS) id 8.3.485.1; Fri, 22 May 2020 03:34:09 -0700 Received: from PCH.MIT.EDU (localhost.localdomain [127.0.0.1]) by PCH.mit.edu (8.14.7/8.12.8) with ESMTP id 04MANfas009657; Fri, 22 May 2020 06:24:01 -0400 Received: from outgoing-exchange-3.mit.edu (OUTGOING-EXCHANGE-3.MIT.EDU [18.9.28.13]) by PCH.mit.edu (8.14.7/8.12.8) with ESMTP id 04MANe2W009654 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Fri, 22 May 2020 06:23:40 -0400 Received: from w92exedge4.exchange.mit.edu (W92EXEDGE4.EXCHANGE.MIT.EDU [18.7.73.16]) by outgoing-exchange-3.mit.edu (8.14.7/8.12.4) with ESMTP id 04MAOngU025640 for ; Fri, 22 May 2020 06:24:50 -0400 Received: from oc11expo6.exchange.mit.edu (18.9.4.11) by w92exedge4.exchange.mit.edu (18.7.73.16) with Microsoft SMTP Server (TLS) id 15.0.1293.2; Fri, 22 May 2020 06:23:27 -0400 Received: from oc11exhyb5.exchange.mit.edu (18.9.1.110) by oc11expo6.exchange.mit.edu (18.9.4.11) with Microsoft SMTP Server (TLS) id 15.0.1365.1; Fri, 22 May 2020 06:23:39 -0400 Received: from NAM10-BN7-obe.outbound.protection.outlook.com (104.47.70.104) by oc11exhyb5.exchange.mit.edu (18.9.1.110) with Microsoft SMTP Server (TLS) id 15.0.1395.4 via Frontend Transport; Fri, 22 May 2020 06:23:39 -0400 Received: from DM5PR22CA0016.namprd22.prod.outlook.com (2603:10b6:3:101::26) by BYAPR01MB4806.prod.exchangelabs.com (2603:10b6:a03:83::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3021.23; Fri, 22 May 2020 10:23:38 +0000 Received: from DM3NAM03FT051.eop-NAM03.prod.protection.outlook.com (2603:10b6:3:101:cafe::fa) by DM5PR22CA0016.outlook.office365.com (2603:10b6:3:101::26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3021.24 via Frontend Transport; Fri, 22 May 2020 10:23:38 +0000 Received: from mail-oi1-f172.google.com (209.85.167.172) by DM3NAM03FT051.mail.protection.outlook.com (10.152.83.56) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3021.23 via Frontend Transport; Fri, 22 May 2020 10:23:37 +0000 Received: by mail-oi1-f172.google.com with SMTP id s198so8866364oie.6 for ; Fri, 22 May 2020 03:23:37 -0700 (PDT) From: Mike Rigby-Jones To: Microcontroller discussion list - Public. Sender: "piclist-bounces@mit.edu" Date: Fri, 22 May 2020 03:23:24 -0700 Subject: Re: [EE] Light bulb moment (literally) Thread-Topic: [EE] Light bulb moment (literally) Thread-Index: AdYwJIde+mg4IHUlQRWbvYoXVvD1Gg== Message-ID: References: List-Help: List-Subscribe: , List-Unsubscribe: , In-Reply-To: Reply-To: Microcontroller discussion list - Public. Accept-Language: en-US X-MS-Exchange-Organization-AuthAs: Anonymous X-MS-Exchange-Organization-AuthSource: TS500.efplus4.local X-MS-Has-Attach: X-Auto-Response-Suppress: All X-MS-Exchange-Organization-SenderIdResult: TempError X-MS-Exchange-Organization-PRD: mit.edu X-MS-TNEF-Correlator: received-spf: Pass (protection.outlook.com: domain of gmail.com designates 209.85.167.172 as permitted sender) receiver=protection.outlook.com; client-ip=209.85.167.172; helo=mail-oi1-f172.google.com; dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=+uwGM3sXT/9ig7eimdbvcKsmnnHWr0UKPBJnuluYsLw=; b=GL7dmE2U0ut3JIHgxN03vkN8ttJncr0+R2FRMFfyzJmOyUtfN4l9BNsFI7EEDRNf7s JUE9O0zsRzUU0240sJFUrQSlgkUIlzKsF0/QHuevr54oI1zeZUUB2GoC7aBRJVQiXic9 1O5gavu7RF8OFt8micUgYYE2Rok6e2j04sgyXVVi3Cw4S4FGAqsnYOoZTaQHx19VRsBd LrkhRLdzybEM2qTvnVORe7qiwooTF0cHvqFVQ3PWjtkpqJu9UzHvlGFChNCo/sFC2PI8 hjel7zI/p/6wcqyb1ZBeV7ryNSOimxkOiha7IsGjQUt8Kx1ueF5Wfd5qY2oa7s+MNDin /BKA== authentication-results: spf=pass (sender IP is 209.85.167.172) smtp.mailfrom=gmail.com; mit.edu; dkim=pass (signature was verified) header.d=gmail.com;mit.edu; dmarc=pass action=none header.from=gmail.com;compauth=pass reason=100 errors-to: piclist-bounces@mit.edu list-id: "Microcontroller discussion list - Public." list-post: x-beenthere: piclist@mit.edu x-mailman-version: 2.1.6 x-received: by 2002:aca:ac4c:: with SMTP id v73mr1996144oie.132.1590143017057; Fri, 22 May 2020 03:23:37 -0700 (PDT) x-topics: [EE] x-content-filtered-by: Mailman/MimeDel 2.1.6 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Same as the permanent magnet generators used on almost all motorcycles. They almost invariably use shunt regulators which wouldn't be suitable if the generator was a voltage source. Mike On Fri, 22 May 2020, 09:34 David C Brown, wrote: > I have just realised that the traditional "dynamo" used for bicycle > lighting (and which is really) a magneto) is, despite being sold as a 6 > volt machine, a actually a constant current device. > Since both voltage and frequency - hence reactance - rise > approximately linearly with speed the current remains constant. > __________________________________________ > David C Brown > 43 Bings Road > Whaley Bridge > High Peak Phone: 01663 733236 > Derbyshire eMail: dcb.home@gmail.com > SK23 7ND web: www.bings-knowle.co.uk/dcb > > > > > *Sent from my etch-a-sketch* > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .