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Sender: "piclist-bounces@mit.edu" Date: Wed, 9 Dec 2020 02:02:17 -0800 Subject: Re: [EE] Eliminating external noise through PS Thread-Topic: [EE] Eliminating external noise through PS Thread-Index: AdbOE+1nyXUgEQW7Tyy61JFfFv6ftw== Message-ID: References: <5FCFC00E.8040703@narwani.org> List-Help: List-Subscribe: , List-Unsubscribe: , In-Reply-To: <5FCFC00E.8040703@narwani.org> 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 209.85.208.181 as permitted sender) receiver=protection.outlook.com; client-ip=209.85.208.181; helo=mail-lj1-f181.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=5uq72VJxAH8LDYUX99ptaQlCmpaAa6voRByyeiyBL/Y=; b=sMxlIWcYRj6jkREbx7+IAb/6VtNDLH0supRO5Hdr13zw+0VZX4WhsMLPHg/+nkQVBu X03D7QSy850RNCsyNHdnrLiUKkGNrfNCKmNww3HyXSrFInIQsqoA7j210EGxkEn/4unR d6DWYmzB65RUzlQ76dSrgfa/pbgNw4p7VLODSS7o5V219rbdP/U61B5fNonK9uLCre5w nRnUEzR8KD59hzUbQQJFMEKqzZfSEkFKUsn6UIp+2mgR+9hPTGX1i6RZTNwxV9Kz2Xic cGyefetE+267E7MusLuZtT8BqJ1Busm499tq/tSPP/csBIU2c/hdr9PMPuGijxybxUjs 4NMw== authentication-results: spf=pass (sender IP is 209.85.208.181) 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; 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:a2e:6a1a:: with SMTP id f26mr773397ljc.416.1607508174494; Wed, 09 Dec 2020 02:02:54 -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 Wed, 9 Dec 2020 at 07:05, Neil wrote: > Hi, > > I'm working on a device that takes 120VAC, converts to 5VDC with a > PCB-mounted power supply, then further reduces that to 3.3VDC with a > linear regulator. > A 3.3V microcontroller switches a relay to power a 120VAC pump. > Overview... > http://orlandorobotbuilders.com/stuff/SMNoise/20201207-SMN-00.jpg How are the grounds distributed between the various items? Ideally you want a star with no loops that would allow alternative ground paths between any two modules. In your diagram it's not possible to determine how the ground runs run. 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 .