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; Mon, 20 Jan 2020 20:32:47 -0800 Received: from PCH.MIT.EDU (localhost.localdomain [127.0.0.1]) by PCH.mit.edu (8.14.7/8.12.8) with ESMTP id 00L4LxvJ001904; Mon, 20 Jan 2020 23:24:18 -0500 Received: from outgoing-exchange-1.mit.edu (OUTGOING-EXCHANGE-1.MIT.EDU [18.9.28.15]) by PCH.mit.edu (8.14.7/8.12.8) with ESMTP id 00L4LwTR001901 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Mon, 20 Jan 2020 23:21:58 -0500 Received: from w92exedge3.exchange.mit.edu (W92EXEDGE3.EXCHANGE.MIT.EDU [18.7.73.15]) by outgoing-exchange-1.mit.edu (8.14.7/8.12.4) with ESMTP id 00L4MO5m001301 for ; Mon, 20 Jan 2020 23:22:33 -0500 Received: from w92expo29.exchange.mit.edu (18.7.74.41) by w92exedge3.exchange.mit.edu (18.7.73.15) with Microsoft SMTP Server (TLS) id 15.0.1293.2; Mon, 20 Jan 2020 23:20:13 -0500 Received: from oc11exhyb3.exchange.mit.edu (18.9.1.99) by w92expo29.exchange.mit.edu (18.7.74.41) with Microsoft SMTP Server (TLS) id 15.0.1365.1; Mon, 20 Jan 2020 23:21:56 -0500 Received: from NAM10-BN7-obe.outbound.protection.outlook.com (104.47.70.100) by oc11exhyb3.exchange.mit.edu (18.9.1.99) with Microsoft SMTP Server (TLS) id 15.0.1395.4 via Frontend Transport; Mon, 20 Jan 2020 23:21:56 -0500 Received: from CY4PR01CA0016.prod.exchangelabs.com (2603:10b6:903:1f::26) by DM5PR0101MB3020.prod.exchangelabs.com (2603:10b6:4:30::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2644.25; Tue, 21 Jan 2020 04:21:52 +0000 Received: from CO1NAM03FT033.eop-NAM03.prod.protection.outlook.com (2a01:111:f400:7e48::200) by CY4PR01CA0016.outlook.office365.com (2603:10b6:903:1f::26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2644.20 via Frontend Transport; Tue, 21 Jan 2020 04:21:51 +0000 Received: from mail-ed1-f46.google.com (209.85.208.46) by CO1NAM03FT033.mail.protection.outlook.com (10.152.80.175) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2644.19 via Frontend Transport; Tue, 21 Jan 2020 04:21:50 +0000 Received: by mail-ed1-f46.google.com with SMTP id bx28so1605970edb.11 for ; Mon, 20 Jan 2020 20:21:49 -0800 (PST) From: RussellMc To: Microcontroller discussion list - Public. Sender: "piclist-bounces@mit.edu" Date: Mon, 20 Jan 2020 20:21:07 -0800 Subject: Re: [EE] Diode bridge failure Thread-Topic: [EE] Diode bridge failure Thread-Index: AdXQE9Vw9jvbjzt2RZKAMe2k6Wi0nQ== 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: Pass X-MS-Exchange-Organization-PRD: mit.edu X-MS-TNEF-Correlator: received-spf: Pass (protection.outlook.com: domain of gmail.com designates 209.85.208.46 as permitted sender) receiver=protection.outlook.com; client-ip=209.85.208.46; helo=mail-ed1-f46.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=VU3srhvGf7dyz8j3+9sCY31TRCC1VJmEOo9N7vKeR6E=; b=Up19HYDLmHr5YQ3j13AhX9FXfsHah94qI5ne17Yt1DheEoYWyvhSfLX8bWldqItzX5 aXlF843NhyqjWzoC4D0OfjGdNdTJMBZap72esDCC+IIFSBIGXbL0fm7MU+k0Cu1BKNJr KkcvKMmw1x92gyjjdX4TjwrJk3XJ6Y2hLuKlxXGHK0JaG2oebEl73gXXCo27zvsXuLnJ vuK/NCtrHU6tC8OmhMwqq/6XeKIlwN58JqWa2qADuknwmoZcz3OhLRkGmaCK5296Q4GI 0Wk4LFe+w7QDlFtPyKEkYol8zEPOZc3ohhp9HW0xZATo4i/ykpNHRjWVnEYn7BxZ8Fxm xgXA== authentication-results: spf=pass (sender IP is 209.85.208.46) 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:aa7:c446:: with SMTP id n6mr2205909edr.320.1579580505404; Mon, 20 Jan 2020 20:21:45 -0800 (PST) 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 On Tue, 21 Jan 2020 at 15:17, David Duffy (AVD) < david@audiovisualdevices.com.au> wrote: > I have a bit of a mystery on my hands. A client of mine has a board that > monitors the output of a 24V transformer. > > The inputs to the board go to a 56V MOV then on to a 0.5A 600V diode > bridge. The - output of the bridge goes to the board's 0V and the + > goes via a resistor divider to a buffer opamp, then off to the micro. > > Is there a filter capacitor? If so, what size? And what sort of impedance / lead lengths between cap and transformer. An inductor has worst case current inrush when input is applied at the voltage zero crossing. How that interacts with max capacitor load (or max load load) depends somewhat on the circuit details. Russell --=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 .