I have a circuit that seems to work well: The lock indicator is a weak source but a good sink so it interfaces more naturally with a pnp or p-channel device. Pull it up to 5V with 100K and connect this point to the gate of a P channel Mosfet whose source is also connected to 5V. Connect the drain of the mosfet to a LED anode and take the LED cathode via 220 R to 0V. This way, the sense of the indicator is correct (0n = lock) and the drive capability of the lock signal works in your favour.
Chris Stake > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Bob Camp > Sent: 22 September 2013 18:53 > To: Bob Stewart; Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator > > Hi > > If you want 10 ma through the LED (which should be plenty) then the > collector resistor would be right around 1.2K > > Bob > > On Sep 22, 2013, at 1:32 PM, Bob Stewart <b...@evoria.net> wrote: > > > D'oh, that should say "I could increase the COLLECTOR resistor to 1500 > ohms". > > > > > > > > > >> ________________________________ > >> From: Bob Stewart <b...@evoria.net> > >> To: Discussion of precise time and frequency measurement > >> <time-nuts@febo.com> > >> Sent: Sunday, September 22, 2013 12:27 PM > >> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator > >> > >> > >> Except that it doesn't work with even 1500 ohms in the base lead. The > LED immediately comes on and stays on. I could increase the emitter > resistor to 1500 ohms and get around 8.5-9ma through the LED, but I'm done > playing with it until I get a proper box to put it all in. This is just a > random 3mm LED out of an HP 37203A, so maybe that has something to do with > it? I haven't looked at the specs. > >> > >> Bob > >> > >> > >> > >> > >> > >>> ________________________________ > >>> From: Bob Camp <li...@rtty.us> > >>> To: Discussion of precise time and frequency measurement > >>> <time-nuts@febo.com> > >>> Sent: Sunday, September 22, 2013 12:12 PM > >>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator > >>> > >>> > >>> Hi > >>> > >>> Circuit should be: > >>> > >>> 2N2222 with emitter to ground, collector to LED, base to lock indicator > via the 4.7K resistor. The LED is hooked to +15 via another resistor. > >>> > >>> If you have ~ 10 ma in the LED then the base needs less than 0.1 ma to > do the job with a 2222. A 4.7K should be plenty. > >>> > >>> Alternate circuit: > >>> > >>> 2N2222 with base to lock indicator / no resistor at all, emitter to > ground via a 1K resistor, collector to LED. LED to +15 via a 1.5K resistor. > >>> > >>> Either one should work. Both turn on the LED when the output is high > and off when the output is low. In order to turn on when it's high you need > to get an inversion ahead of the 2N2222. > >>> > >>> Bob > >>> > >>> > >>> On Sep 22, 2013, at 12:17 PM, Bob Stewart <b...@evoria.net> wrote: > >>> > >>>> Hi Bob, > >>>> > >>>> I tried 4700 and even 1500, but they're too large. I guess the little > flash of the LED at power-on is the hint that 1K is right at the ragged > edge. It would probably make a big difference if there was a 100 or even > 47 ohm resistor between the emitter and the LED, but my little board is > starting to get burnt up, wires are starting to get frayed, and it does > work, so this cake is done. > >>>> > >>>> Bob > >>>> > >>>> > >>>> > >>>> > >>>> > >>>>> ________________________________ > >>>>> From: Bob Camp <li...@rtty.us> > >>>>> To: Discussion of precise time and frequency measurement > >>>>> <time-nuts@febo.com> > >>>>> Sent: Sunday, September 22, 2013 6:31 AM > >>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator > >>>>> > >>>>> > >>>>> Hi > >>>>> > >>>>> If you trace out the chip that drives the lock indicator it's got > some sort of strange gating in it's supply pin. That gets you even less > output than you would expect from a CMOS gate. I would not count on it > putting out more than 1 ma at 5 volts. A 4.7K resistor to the 2N2222 base > should be about right. > >>>>> > >>>>> Bob > >>>>> > >>>>> On Sep 21, 2013, at 10:34 PM, Bob Stewart <b...@evoria.net> wrote: > >>>>> > >>>>>> Thanks for the heads-up, Bob. I'll do it the next time the iron is > hot. Fortunately, it's only on for about a minute or so, then there's no > drive from the FE-5680A. Is 3ma really that big a deal? I know squat > about CMOS gates. I guess it is pulling the voltage down by 25%, though. > >>>>>> > >>>>>> Bob > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>>> ________________________________ > >>>>>>> From: Robert LaJeunesse <rlajeune...@sbcglobal.net> > >>>>>>> To: Bob Stewart <b...@evoria.net>; Discussion of precise time and > >>>>>>> frequency measurement <time-nuts@febo.com> > >>>>>>> Sent: Saturday, September 21, 2013 9:24 PM > >>>>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> Bob, > >>>>>>> > >>>>>>> > >>>>>>> I would bump that base resistor up a lot higher, to load the FE- > 5680 less. The PN2222 has enough gain it only needs about 0.3 mA base drive > to work as intended. You'd get that with a 10K base resistor. > >>>>>>> > >>>>>>> > >>>>>>> Bob LaJeunesse > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>>> ________________________________ > >>>>>>>> From: Bob Stewart <b...@evoria.net> > >>>>>>>> To: Time Nuts <time-nuts@febo.com> > >>>>>>>> Sent: Saturday, September 21, 2013 10:02 PM > >>>>>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator > >>>>>>>> > >>>>>>>> > >>>>>>>> Hi John, > >>>>>>>> > >>>>>>>> Thanks for the response. I managed to cobble something up with > >>>>>>>> LTSpiceIV, and get it to work. And for me, that's saying > >>>>>> something! Here's what I wound up with: > "http://www.evoria.net/AE6RV/GPSstd_PLL/LED-driver.png", where V2 is the > Loop Lock Indicator. The PN2222 shorts out the LED until it goes into > lock, then the LED comes on. It does give a short pulse when power is > first applied and things are equalizing. Even with a 1K resistor, the 4.2V > from Lock signal is pulled down to 3V. > >>>>>>>> > >>>>>>>> And here's a pic of my Rb standard on it's temporary home with the > LED on a scrap of breadboard: > >>>>>>>> "http://www.evoria.net/AE6RV/GPSstd_PLL/Rb.standard.png". > >>>>>>>> > >>>>>>>> Bob > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>>> ________________________________ > >>>>>>>>> From: jmfranke <jmfra...@cox.net> > >>>>>>>>> To: Bob Stewart <b...@evoria.net>; Discussion of precise time > >>>>>>>>> and frequency measurement <time-nuts@febo.com> > >>>>>>>>> Sent: Saturday, September 21, 2013 6:58 PM > >>>>>>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> 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 > >>>>>>>>>>>>>> _______________________________________________ > >>>>>>>>>>>>>> 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. > >>>>>>>>>>>>> > >>>>>>>>>>>>> > >>>>>>>>>>>>> > >>>>>>>>>>>> _______________________________________________ > >>>>>>>>>>>> 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. > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>> _______________________________________________ > >>>>>>>>>> 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. > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>> > >>>>>>> > >>>>>> _______________________________________________ > >>>>>> 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. > >>>>> > >>>>> > >>>>> > >>>> _______________________________________________ > >>>> 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. > >>> > >>> > >>> > >> _______________________________________________ > >> 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. > > _______________________________________________ > 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.