Low noise power supplies?
Joe,
I'm using that in my low power (150ma) supplies. I add a zener to the base (darlington) circuit for pre-regulation. Since I'm doing a line operated linear supply the fall off of gain with frequency is not of too much concern.
Once I finish testing (I have boards in hand - I need to order parts) I will publish.
Simon
Message: 6
Date: Thu, 31 Jan 2013 15:39:02 -0500
From: Joe Leikhim jleikhim@leikhim.com
To: time-nuts@febo.com
Subject: [time-nuts] Low noise power supplies?
Message-ID: 510AD666.8090908@leikhim.com
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Back when I was in product engineering there was a VCO design that used
a "superfilter" circuit. It consisted of a pass transistor and a filter
cap from base to ground. The gain of the transistor multiplied the
effective capacitance. I have not seen this configuration since.
--
Joe Leikhim
Leikhim and Associates
Communications Consultants
Oviedo, Florida
407-982-0446
Engineering is the art of making what you want from what you can get at a profit.
Hi
If you use an electrolytic cap on the base (tantalum or what ever) the
leakage current will mess up the output a bit. It does eventually die down
some, but you may have to wait for days...
Bob
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of M. Simon
Sent: Friday, February 01, 2013 9:11 AM
To: time-nuts@febo.com; jleikhim@leikhim.com
Subject: [time-nuts] Low noise power supplies?
Joe,
I'm using that in my low power (150ma) supplies. I add a zener to the base
(darlington) circuit for pre-regulation. Since I'm doing a line operated
linear supply the fall off of gain with frequency is not of too much
concern.
Once I finish testing (I have boards in hand - I need to order parts) I
will publish.
Simon
Message: 6
Date: Thu, 31 Jan 2013 15:39:02 -0500
From: Joe Leikhim jleikhim@leikhim.com
To: time-nuts@febo.com
Subject: [time-nuts] Low noise power supplies?
Message-ID: 510AD666.8090908@leikhim.com
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Back when I was in product engineering there was a VCO design that used
a "superfilter" circuit. It consisted of a pass transistor and a filter
cap from base to ground. The gain of the transistor multiplied the
effective capacitance. I have not seen this configuration since.
--
Joe Leikhim
Leikhim and Associates
Communications Consultants
Oviedo, Florida
407-982-0446
Engineering is the art of making what you want from what you can get at a
profit.
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