Yes, but put an isolation resistor between the output and the base of the
transistor, something between 3K and 5K should work. The LED will light upon
power on and extinguish when lock is achieved.
John WA4WDL
--------------------------------------------------
From: "Bob Stewart" <b...@evoria.net>
Sent: Saturday, September 21, 2013 6:10 PM
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
Hi Bob,
I hooked the big voltmeter up to it, and it shows +4.2V out for about a
minute, and then goes to 0. Looking on the web, it seems like I can use
that to drive a 2N2222 and put the LED and dropping resistor in the
collector path with the emitter to ground? Does that sound right?
Bob
________________________________
From: Bob Camp <li...@rtty.us>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Sent: Saturday, September 21, 2013 4:12 PM
Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
Hi
Those readings sound a lot more like a CMOS gate output than some sort of
open drain / open collector discrete driver.
Bob
On Sep 21, 2013, at 4:43 PM, Bob Stewart <b...@evoria.net> wrote:
Hi Bob,
It's rather curious. Using my handheld DVM in the diode scale, I get a
reading of 448 in one direction and 458 in the other with it off and
cold. In the 2K ohms scale, I get 561 and 562 ohms. Later on, I'll pop
the top off again and take a pic so I can expand it and look at it. For
what it's worth, my DDS board is 2 revisions earlier than the one
Matthias Bopp modifies here
"http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%201_0.pdf";
Bob
________________________________
From: Bob Camp <li...@rtty.us>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Sent: Saturday, September 21, 2013 3:00 PM
Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
Hi
As far as I know the lock output is a CMOS output that will drive a
couple of ma. There are so many variations that yours may indeed be an
open collector and good to +15 volts.
Bob
On Sep 21, 2013, at 10:55 AM, Bob Stewart <b...@evoria.net> wrote:
The instructions I got with this Rb said that you could hook an LED
through a 5-10K resistor to the +15 supply and get a lock indication.
I'm using a 10K resistor and the LED lights as soon as it's powered up
from cold. Is the loop lock indicator circuit broken or is it just
another strange option for these things? I saw on one site that if you
do it this way it prevents lock, but mine seems to lock OK with or
without the voltage.
Bob - AE6RV
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