Well the Tek current probe that goes in the power supply wasn't low cost. They also had a nice bench supply that went in the box. But a lot of the instruments weren't so fancy. -----Original Message----- From: "Max Robinson" <m...@maxsmusicplace.com> Sender: time-nuts-boun...@febo.com Date: Fri, 1 Feb 2013 13:39:14 To: Discussion of precise time and frequency measurement<time-nuts@febo.com> Reply-To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Subject: Re: [time-nuts] Low noise power supplies?
Well, I stand corrected. Weren't the TM 500 instruments marketed as low cost? Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com ----- Original Message ----- From: "David" <davidwh...@gmail.com> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Thursday, January 31, 2013 11:10 PM Subject: Re: [time-nuts] Low noise power supplies? >I have seen it used in a couple of Tektronix TM500 instruments but the > purpose may have been to generate a lower voltage power supply rail > instead of noise reduction. Tektronix often added LC sections on > their switching power supply outputs and distributed smaller LC > sections to prevent coupling between different circuits. > > On Thu, 31 Jan 2013 22:12:42 -0600, "Max Robinson" > <m...@maxsmusicplace.com> wrote: > >>You haven't seen it used because it doesn't work very well. It appeared >>in >>a few pieces of Heathkit equipment but I don't think HP or Tek used it at >>all. Any AC component of base to collector voltage has a small but >>definite >>effect on Vbe which transfers voltage in the reverse direction from >>collector to emitter even though the base is held at AC ground. A three >>terminal regulator does a better job of suppressing ripple from a power >>supply. >> >>Regulators use a zener diode as the reference and there are circuits in >>which a zener is used as a noise source. What does that tell you? The >>quietest power supply is an analog regulator followed by one or more RC >>filter sections. The inductor in an LC filter is likely to pick up more >>hum >>and noise than it filters out. My presumption is that a low noise power >>supply is likely to be providing a small amount of power to the load and >>load regulation is probably not a problem. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.