[ARC5] [Milsurplus] Sandy Coolness for Our BAs

[Tom Lee]

The ones I've encountered in the past were very good at exploding during 
an unscheduled screwdriver test, so Dennis has an excellent point. These 
are very simple regulators, so their short-circuit protection consists 
of instructions to the user not to short it.

--Cheers,
Tom

-- 
Prof. Thomas H. Lee
Allen Bldg., CIS-205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu
650-725-3383 (public fax; no confidential information, please)

On 5/12/2017 11:25 PM, Dennis Monticelli wrote:
> The one transistor NPN control device probably just has a zener 
> between its emitter and ground.  A resistor divider across the output 
> has its tap connected to the base of that NPN.
>
> I don't know what the SOA of that Darlington is or if there is another 
> NPN in there serving as a current limit.  In other words it may not 
> survive a screwdriver short so beware.
>
> Dennis AE6C
>
> On Fri, May 12, 2017 at 10:15 PM, David Stinson <arc5 at ix.netcom.com 
> <mailto:arc5 at ix.netcom.com>> wrote:
>
>     ----- Original Message ----- From: "Tom Lee"
>     <tomlee at ee.stanford.edu <mailto:tomlee at ee.stanford.edu>>
>     Subject: Re: [ARC5] [Milsurplus] Sandy Coolness for Our BAs
>
>         If this part is like some of the TV regulators I've
>         encountered in the
>         past, the base terminal needs to be pulled up to the
>         unregulated input
>         voltage through a resistor. Depending on the input-output
>         differential
>         you seek, the resistor will be of the order of 10k or so,
>         typically.
>         Frequency compensation is also frequently required, and the base
>         terminal is a convenient place to connect an appropriate
>         stabilization
>         network (e.g., C or series RC to ground).
>
>
>     Mr. Tom Lee was exactly correct.
>     Many thanks also to Bob AH7I, and
>     John Kidd from Australia for more info
>     and details.
>     10 K from INPUT to BIAS, .1 uFd
>     from BIAS to COMMON and 10 uFd on
>     the OUTPUT, similar to what one would do
>     with a common low-V regulator.
>     The isolation transformer, bridge and
>     47 mFd filter is supplying ripply 180V
>     peak to the regulator device.
>     A nice, clean and steady 135V is
>     running the receiver.
>
>     Gentlemen like you continue to prove
>     that my confidence in our community
>     is well-founded.
>
>     TNX OM ES 73 DE Dave AB5S
>
>
>
>     ----- Original Message ----- From: "Tom Lee"
>     <tomlee at ee.stanford.edu <mailto:tomlee at ee.stanford.edu>>
>     Subject: Re: [ARC5] [Milsurplus] Sandy Coolness for Our BAs
>
>
>         If this part is like some of the TV regulators I've
>         encountered in the
>         past, the base terminal needs to be pulled up to the
>         unregulated input
>         voltage through a resistor. Depending on the input-output
>         differential
>         you seek, the resistor will be of the order of 10k or so,
>         typically.
>         Frequency compensation is also frequently required, and the base
>         terminal is a convenient place to connect an appropriate
>         stabilization
>         network (e.g., C or series RC to ground).
>
>
>     ______________________________________________________________
>     ARC5 mailing list
>     Home: http://mailman.qth.net/mailman/listinfo/arc5
>     <http://mailman.qth.net/mailman/listinfo/arc5>
>     Help: http://mailman.qth.net/mmfaq.htm
>     <http://mailman.qth.net/mmfaq.htm>
>     Post: mailto:ARC5 at mailman.qth.net <mailto:ARC5 at mailman.qth.net>
>
>     This list hosted by: http://www.qsl.net
>     Please help support this email list: http://www.qsl.net/donate.html
>
>
>
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20170512/4031a361/attachment-0001.html>