Return-Path: X-Spam-DCC: paranoid 1356; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,HTML_MESSAGE autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id t9VHVKWD012214 for ; Sat, 31 Oct 2015 18:31:20 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZsZwv-0005U5-80 for rs_out_1@blacksheep.org; Sat, 31 Oct 2015 17:28:17 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZsZwu-0005Tp-LY for rsgb_lf_group@blacksheep.org; Sat, 31 Oct 2015 17:28:16 +0000 Received: from mail-wm0-f46.google.com ([74.125.82.46]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1ZsZvt-0002ra-RY for rsgb_lf_group@blacksheep.org; Sat, 31 Oct 2015 17:28:15 +0000 Received: by wmeg8 with SMTP id g8so31555886wme.0 for ; Sat, 31 Oct 2015 10:26:57 -0700 (PDT) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=uHQTwDFuwWvRUHsgk3eMHlJGmhEAVxfMUj16z1SCWN8=; b=rxPT4FLw15DPFHNso/zinVrloRHUbsiHJZcrv7NaJauCiFkVfnCTWTnz4DsvjXZpzk 8Gt2M9/5+HcRpkpw61UJKR9IKxzQvX+CZPBsByxEZozMPZK6b1s/VyPerTmmPpuTZ8sc bv9aNb0SQcOuoFJFmSrJglw0o1f2u/viirAalmaD+IxCvZxaQ/JOoG7fwBN+SjOICDSe caa1NaehWSWw33RFi2ZDBrSHkop7oFzykADvVgBRol/1M71cWvFTEzSh/kUgyDWG96H7 gDJigI1NqlTYN/VYnlXq+kllbWsNUvFi+SObhMgDP944czt8idzkhb3TB4gqK3D+R+jW c+lQ== MIME-Version: 1.0 X-Received: by 10.28.12.140 with SMTP id 134mr4719920wmm.9.1446312417923; Sat, 31 Oct 2015 10:26:57 -0700 (PDT) Received: by 10.28.183.139 with HTTP; Sat, 31 Oct 2015 10:26:57 -0700 (PDT) In-Reply-To: <994616020.20151031170025@chriswilson.tv> References: <1981852865.20151017122027@chriswilson.tv> <1530BFEB-9BC2-4CA2-A7A3-338629A98202@me.com> <308511169.20151029202607@chriswilson.tv> <56328B1F.2080901@posteo.de> <12510142154.20151030112719@chriswilson.tv> <5633C6F8.4080807@posteo.de> <984267409.20151031132006@chriswilson.tv> <994616020.20151031170025@chriswilson.tv> Date: Sat, 31 Oct 2015 17:26:57 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org X-Scan-Signature: 47a967f57bae6380aac0a0062beb1b4e Subject: Re: Re[4]: LF: Automatic variometer circuit Content-Type: multipart/alternative; boundary=001a11444e3ce79713052369d993 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 4733 --001a11444e3ce79713052369d993 Content-Type: text/plain; charset=UTF-8 Yes, Indeed Andy On 31 October 2015 at 17:00, Chris Wilson wrote: > Hello Andy, > > Saturday, October 31, 2015 > > > Is this what you mean? > > http://www.chriswilson.tv/phase-driver.jpg > > Thanks. > > > > Actually, looking again at the circuit again, it is not necessary > > to use an opamp in that position to define the mid rail for the > > comparator reference. Just two equal; value resistors and > > oneelectrolytic decoupling the junction to ground (Definitely not > > two caps to top and bottom in the original configuration shown ... think > about it...) > > > > You only need an opamp to define a stiff mid rail voltage where > > there is likely to be any significant current draw. Or many stages > > need to be referenced to it - such as a multi stage filter. For > > single stage configurations, just two resistors and a bit of decoupling > is enough > > > > > > > > > > -- > Best regards, > Chris mailto:chris@chriswilson.tv > > > --001a11444e3ce79713052369d993 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Yes, Indeed

Andy

On 31 October 2015 at 17:00, Chris= Wilson <chris@chriswilson.tv> wrote:
Hello Andy,

Saturday, October 31, 2015


Is this what you mean?

http://www.chriswilson.tv/phase-driver.jpg

Thanks.


> Actually, looking again at the circuit again, it is not necessary
> to use an opamp in that position to define the mid rail for the
> comparator reference. =C2=A0 =C2=A0Just two equal; value resistors and=
> oneelectrolytic decoupling the junction to ground (Definitely not
> two caps to top and bottom in the original configuration shown ... thi= nk about it...) =C2=A0


> You only need an opamp to define a stiff mid rail voltage where
> there is likely to be any significant current draw.=C2=A0 Or many stag= es
> need to be referenced to it - such as a multi stage filter. =C2=A0 =C2= =A0For
> single stage configurations, just two resistors and a bit of decouplin= g is enough









--
Best regards,
=C2=A0Chris=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 mailto:chris@chriswilson.tv



--001a11444e3ce79713052369d993--