Use the buck/boost knurdle to lower the voltage, followed by a low noise linear regulator. Quiet and efficient... Don
Bob Camp > Hi > > The OCXO in the TBolt has a linear controller. It drops back to about > 150 to 250 ma on the +12 line after warmup. It's been at least 40 years > since I saw an on/off oven control in production . > > Remember that the +12 feeds the oscillator circuit. The more crud on the > 12 volts, the worse the phase noise of the output. A linear regulator is > a good idea. > > Bob > > On Jun 27, 2013, at 3:49 PM, Bob Stewart <b...@evoria.net> wrote: > >> Hi Hal and other responders, >> >> I believe that the OCXO uses an ON-OFF type of regulation. So, no, it >> doesn't use 1A all the time. Maybe I should just put an ammeter in >> the line and see what kind of duty cycle it has after it's at >> temperature. >> >> >> I tried a 7812 regulator with a small dissipator on it. It goes into >> overheat mode almost immediately and the output voltage starts quickly >> doing down. The case does have provisions for a single TO-3 >> transistor conducting heat to the back of the case with no radiating >> fins. I had briefly considered using a zener and a 2N3055. >> >> I think that instead of worrying this to death, I'm just going to use >> a brick to get it together, and then if something comes up later that >> I like, I'll put that in. I did like the looks of that PT5102 but >> it's at end of life, and 1A is right at it's limit. I've given some >> consideration to seeing whether I can pull a few turns off the >> transformer secondary, as well. >> >> >> Bob - AE6RV >> >> >> >> ----- Original Message ----- >>> From: Hal Murray <hmur...@megapathdsl.net> >>> To: Bob Stewart <b...@evoria.net>; Discussion of precise time and >>> frequency measurement <time-nuts@febo.com> >>> Cc: hmur...@megapathdsl.net >>> Sent: Thursday, June 27, 2013 2:24 PM >>> Subject: Re: [time-nuts] +12 Volts 1A (plus a bit) supply? >>> >>> >>> b...@evoria.net said: >>>> The transformer gives me about 20 volts DC out. Dropping 8 volts at >>>> 1 amp >>>> is just a lot of power to void with a resistor. I'd like to avoid >>> having >>>> that much waste heat in the unit. >>> >>> Does it really take 1A after it's warmed up? >> _______________________________________________ >> 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. > > -- "Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind." De Erroribus Medicorum, R. Bacon, 13th century. "If you don't know what it is, don't poke it." Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 Skype: buffler2 www.lightningforensics.com www.sixmilesystems.com _______________________________________________ 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.