Noticed an odd effect w/4060 - can someone explain?

No_6 · Post by **No_6** » Sun Mar 07, 2010 4:35 am

Due to my recent modelling, er, mishap, I've been taking a break and playing around with a 4060 chip and a variety of capacitors. Just for yucks, I soldered 2 capacitors marked "10" together and hooked it up. I was rewarded with a seemingly random blinking pattern. Both on and off states jvaried in length. I then did the same thing with a pair of capacitors marked "1." With this configuration, I achieved a flickering, candle-like effect, though the 'off' states were so short, it never appeared dark.

However, when I reconnected the dual 10s, I was unable to duplicate the random blinking pattern, with every (functional) configuration returning a regular blinking pattern. Reconnecting the dual 1's and it was the same story.

Can anyone explain what happened here? It sure would be nice to be able to consistently reproduce those effects with such a simple set-up.

Scott Hasty · Post by **Scott Hasty** » Sun Mar 07, 2010 9:08 am

How were the caps soldered, series or parallel? What pin of the 4060 was used to get this effect? What kind of voltage and current were you using?

No_6 · Post by **No_6** » Sun Mar 07, 2010 2:57 pm

The caps were soldered in series. Can't remember what pins I was using... #2 and #10 I think (counting clockwise from the power pin). Running 12V, 1000ma.

Scott Hasty · Post by **Scott Hasty** » Sun Mar 07, 2010 3:56 pm

Not knowing the schematic or the exact 4060 I can only guess. Some 4060's can't handle more than 5V, so it could be damaged. If you had a full load and ran an amp through it, it is certainly damaged, but there would have probably been smoke. It could be an RC circuit if any resistance is part of your circuit.

macfrank · Post by **macfrank** » Sun Mar 07, 2010 5:09 pm

CMOS devices are both static sensitive and have high impedance inputs, so unused inputs have to be tied to ground or a voltage. The 4060 only has one potentially unused input - reset - so if you left it floating, it may have been resetting on its own. CMOS devices can sometimes seem to work even though no power is applied to them, so check the power leads.

No_6 · Post by **No_6** » Sun Mar 07, 2010 5:38 pm

Hm... no smoke. And it seems to be working completely normally now. I've regularly run 12v through the 4060 chips I have, for extended periods of time, with no problems. In my actual builds I usually break off the unused leads and then use epoxy to insulate the exposed metal and stick the chip in place.

macfrank · Post by **macfrank** » Sun Mar 07, 2010 6:07 pm

No_6 wrote:In my actual builds I usually break off the unused leads and then use epoxy to insulate the exposed metal and stick the chip in place.

If you're using a real CMOS device, (40xxc series or even 74Cxxx series) you really do have to connect unused inputs to V+ or ground - tearing the pin off isn't the same thing.

Not doing so may result in unexpected behavior or the device may lock up; it could be permanently damaged.

en'til Zog · Post by **en'til Zog** » Tue Mar 09, 2010 11:28 pm

If the reset pin isn't connected to negative - or anything - it's acting as an antenna, bringing into the chip any static, or radio/T.V. station that might be in the area causing it try and count the noise.

You might have had a loose connection with the timing resistor which could be another "antenna".

No_6 · Post by **No_6** » Sat Mar 13, 2010 9:44 pm

en'til Zog wrote:If the reset pin isn't connected to negative - or anything - it's acting as an antenna, bringing into the chip any static, or radio/T.V. station that might be in the area causing it try and count the noise.

You might have had a loose connection with the timing resistor which could be another "antenna".

Interesting... so... were one to solder the antenna from an AM radio to the reset pin... ?

BTW, is it true that breaking off unused pins could lead to the failure of the chip?

en'til Zog · Post by **en'til Zog** » Sun Mar 14, 2010 1:18 am

INPUTS - the three clock pins AND RESET - must be used or connected to something like NEGATIVE. You can leave unused OUTPUT pins alone, or clip 'em off. Just breaking 'em off could stress the internal connections between the pin and the internal flake of Silicon that's the "real" chip inside.

As for connecting an ant-enna to RESET or any other INPUT pin, remember the ship is highly static sensative. The spark you get in winter between your finger and a light switch is about 16,000 volts. Way more than a CMOS ship is happy with. Now, if you connect a short length of insullated wire to an INPUT Pin making sure it can't touch anything else... that chould work.

Try it! Let us know how it works.