I hadn't thought of using a pullup resistor. I'd have to get out the calculator to see if it's worth it, though. It's only taking a load for a minute or two till it locks, so I don't think it's a problem.
Bob >________________________________ > From: Chris Stake <st...@btinternet.com> >To: 'Discussion of precise time and frequency measurement' ><time-nuts@febo.com>; 'Bob Stewart' <b...@evoria.net> >Sent: Sunday, September 22, 2013 2:06 PM >Subject: RE: [time-nuts] FE-5680A Loop Lock Indicator > > >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.