I'm using a 556 dual timer, one section as an inverter to drive a lock led, and the other section as a pulse stretcher to drive a 1 pps led. Let's get on with it. Don
Attila Kinali > On Fri, 3 Feb 2012 09:50:52 -0000 > "Rob Kimberley" <[email protected]> wrote: > >> Mine was a green LED out of the junk box, but I did use 330R in >> series. 1k8 >> seems rather large. > > Then i'm not surprised that your FE-5680 refused to work :-) > > Just calculate: 5V supply, approx 2V LED voltage -> 3V over the > resistor. > 3V/330R = 90mA. As i wrote already, the 74AC240 has it's absolute > maximum rating at 50mA. For a general logic output, i wouldn't recomend > to draw more than 10mA (as Bob Grant wrote, the lock signal doesn't > seem to pass trough the 74AC240). Hence, i would say that 330R seems > rather small :-) > > Keep in mind that you drove circuit at over current for quite a long > time. The circuit is most likely damaged (if they dont have an over > current limit, which i doubt). If for an unknown reason the lock signal > fails in the future, it might be due to this. > > Attila Kinali > -- > The trouble with you, Shev, is you don't say anything until you've saved > up a whole truckload of damned heavy brick arguments and then you dump > them all out and never look at the bleeding body mangled beneath the > heap > -- Tirin, The Dispossessed, U. Le Guin > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- "Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind." R. Bacon "If you don't know what it is, don't poke it." Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
