[time-nuts] Low noise power supplies?

[Bob Camp]

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 at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of M. Simon
Sent: Friday, February 01, 2013 9:11 AM
To: time-nuts at febo.com; jleikhim at 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 at leikhim.com>
To: time-nuts at febo.com
Subject: [time-nuts]  Low noise power supplies?
Message-ID: <510AD666.8090908 at 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

JLeikhim at Leikhim.com

407-982-0446

WWW.LEIKHIM.COM

 



Engineering is the art of making what you want from what you can get at a
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