Are you referring to the 4060? It has an internal oscillator and a 14-stage counter/divider. It requires some external components for the oscillator, either crystal or RC. The 4020, 4024 and 4040 don't have the oscillator and offer from 7 to 14 stages divider. Cheers, Isaac Em 04/04/2017 07:21, CDB escreveu: > On 04/04/2017 05:15:24, "Dave Lagzdin" wrote: >> and I forget the part >> number of the other one), has an oscillator and should find suitable=20 >> outputs from the dividers > I can't recall if that was a 74xx or 40xx part, I had a quick look=20 > online but couldn't find it. If only I still had my TTL/CMOS logic=20 > books. > > This weekend I'll go through my old magazine compendium books from the=20 > 70s and 80s they may well give my memory a jog. >> -- > colin@btech-online.co.uk > > Web presence: www.btech-online.co.uk > > Hosted by: www.justhost.com.au > > This email is to be considered private if addressed to a named =20 > individual or Personnel Department, and public if addressed to a blog, =20 > forum or news article. > > > __________________________________ > Sent from eM Client | www.emclient.com > > > > On 04/04/2017 05:15:24, "Dave Lagzdin" wrote: > >> I'd probably try playing with an old cmos 4060 ( >> D >> >> On 1 April 2017 at 20:30, CDB wrote: >> >>> I was chatting with someone from work the other day and the=20 >>> conversation >>> turned to them wanting to put an LED on their quadcopter which had a >>> strobing light similar to the navigation light on an aircraft, the=20 >>> one >>> that appears to make quick succession flashes that increase in=20 >>> frequency >>> making it look like one flash-pause pause next flash - pause -flash. >>> This would be easy to do with three LEDs in parallell, light LED 1=20 >>> then >>> LEDs 1 and 2, then LEDs 1,2,3 >>> >>> This got me thinking on how to hypothetically come up with a circuit. >>> >>> The criteria would be: >>> >>> No uP to be used. >>> Vcc =3D 5V >>> One white high brightness LED >>> Flash rate unsure but I suspect around 1 to 2 Hz >>> As few components as possible >>> Small footprint. >>> >>> Now as I tend to come up with complicated ideas and then work=20 >>> backwards >>> to simpler ones, I'm looking for comments and other ideas on what I=20 >>> have >>> thunked up so far. >>> >>> 1. The obsolete LM3909 might fit the bill (still available on Ebay) >>> except I need 3 flashes per period >>> =20 >>> (https://www.digchip.com/datasheets/parts/datasheet/321/LM3909-pdf.php) >>> >>> 2. CD4017/74LS90 decade counter + CD4093/74LS00 NAND gates for >>> oscillator + 1 74LVC1G27 single triple input OR gate chip connecting=20 >>> the >>> decade counter outputs to the LED. >>> >>> 3. 74LS196 decade counter + CD4046 PLL driven by unijunction >>> transistor the idea being the frequency will change with the sawtooth >>> pattern and hence the light pattern will change. >>> >>> 4. CD4048 dual retriggable monostable + 555 as oscillator then OR the >>> two outputs together. >>> >>> 5 Pulse generator using an 74LS10 quad NAND gate + 555 as a clock >>> generator and OR gate at the two pulse outputs driving the LED. >>> >>> I've just thought, I suppose I could use a dual 555 timer + driver >>> transistor. >>> >>> I'm sure back in the 80s there were special one chip flasher chips=20 >>> aimed >>> at toys which did exactly what this circuit needs, but I threw my=20 >>> lovely >>> paper based Maplins catalogue out years ago (1999 to be precise). >>> >>> Comments welcome. >>> >>> Colin >>> >>> >>> >>> -- >>> >>> colin@btech-online.co.uk >>> >>> Web presence: www.btech-online.co.uk >>> >>> Hosted by: www.justhost.com.au >>> >>> This email is to be considered private if addressed to a named >>> individual or Personnel Department, and public if addressed to a=20 >>> blog, >>> forum or news article. >>> >>> >>> >>> __________________________________ >>> Sent from eM Client | www.emclient.com >>> -- >>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>> View/change your membership options at >>> http://mailman.mit.edu/mailman/listinfo/piclist >>> >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist > --- Este email foi escaneado pelo Avast antiv=EDrus. https://www.avast.com/antivirus --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .