Timeline for Manual reset problem: CD4060 timer circuit
Current License: CC BY-SA 3.0
41 events
| when toggle format | what | by | license | comment | |
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| Dec 22, 2018 at 22:55 | comment | added | Chris Stratton | -1 for showing Vdd connected to ground(!) You meant to draw Vss of course, and where you show Vcc should be Vdd. | |
| Dec 22, 2018 at 22:26 | answer | added | Jasen Слава Україні | timeline score: -1 | |
| Dec 22, 2018 at 22:14 | comment | added | Jasen Слава Україні | check that the VDD pin is actually connected to ground. (negative supply) | |
| Dec 22, 2018 at 21:12 | answer | added | paki eng | timeline score: 1 | |
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| Sep 9, 2017 at 16:43 | answer | added | Spehro 'speff' Pefhany | timeline score: 1 | |
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| Jun 6, 2017 at 21:27 | comment | added | Mark Colan | @scorpdaddy: as I understand it, the switch is not to discharge the capacitor; rather, it is to pull pin 12 / RESET hi. But if there is a charge on the capacitor, then of course pushing the button also discharges it. Another comment suggested a 1k resistor in series with the switch, and I'll try that. | |
| Jun 6, 2017 at 21:25 | history | edited | Mark Colan | CC BY-SA 3.0 |
Changed CX RX RS to φ0 !φ0 and φ1 to agree with the linked datasheet
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| Jun 6, 2017 at 21:16 | comment | added | Trevor_G | A 1K or so resistor in series with the switch would help with that. Either that or figure out how to pull the left end of the cap low while in reset. Or both.. | |
| Jun 6, 2017 at 21:16 | history | edited | Mark Colan | CC BY-SA 3.0 |
Updated the diagram: incorrect resistor value, pin numbers outside box, pin names inside box.
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| Jun 6, 2017 at 21:09 | comment | added | Trevor_G | @MarkColan the reset ties into the clock line... as such if it bounced around with spikes that are too short to reset but fast enough to generate a clock edge it might count those. | |
| Jun 6, 2017 at 21:05 | comment | added | Mark Colan | I was going to change the timing/pulldown resistor to 10K. In doing so, I noticed that though the schematic says 1M, the resistor I used was actually 120K (and I don't remember why). Changing it to 10K makes it reset correctly if I push and release the button quickly. If I hold it down for a half second or more, I get a non-zero state, but it is a low number (4 or less). It works well enough as is, but I would like to understand how to make it work absolutely correctly, and why it does not now. | |
| Jun 6, 2017 at 20:53 | comment | added | Mark Colan | The Vcc is 12vdc, regulated. | |
| Jun 6, 2017 at 20:48 | comment | added | Mark Colan | I saw the 1M resistor not as a pull-down, but as a timing resistor with the 100nF capacitor. The timing controls the length of the power-on reset pulse. A common value for pull-downs is 10K, but that will mean a relatively short reset pulse. | |
| Jun 6, 2017 at 20:47 | comment | added | Mark Colan | In my naive view of electronics, "contact bounce" means that for an untreated pushbutton, you might get more than one connection. If that is the case, it seems like it would be reset more than one time. Could you explain why that would cause an incorrect reset? | |
| Jun 6, 2017 at 16:49 | comment | added | TonyM | @Trevor, yes, a monostable in this mode is inherently a debounce circuit. Thanks for putting the datasheet link in. A formatted schematic's best though, attracts a wider audience and hopefully better answers :-) I dunno if what you're calling noise effects are what I'd call pin leakage current effects, with the huge resistors but if so, spot on. | |
| Jun 6, 2017 at 16:34 | comment | added | Trevor_G | @JRE though it WILL bounce for sure, one would imagine that would present itself as more resets and not really be a great problem. | |
| Jun 6, 2017 at 16:34 | comment | added | scorpdaddy | Do you have anything to limit the discharge current through the switch? | |
| Jun 6, 2017 at 16:31 | comment | added | Trevor_G | What is the supply voltage on this circuit? | |
| Jun 6, 2017 at 16:31 | answer | added | Trevor_G | timeline score: 1 | |
| Jun 6, 2017 at 16:23 | comment | added | JRE | Two words: contact bounce. | |
| Jun 6, 2017 at 16:15 | comment | added | Trevor_G | 1M seems a tad high for a pulldown... | |
| Jun 6, 2017 at 16:10 | comment | added | Trevor_G | Data sheet link added @TonyM | |
| Jun 6, 2017 at 16:10 | history | edited | Trevor_G | CC BY-SA 3.0 |
added 63 characters in body
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| Jun 6, 2017 at 16:09 | comment | added | TonyM | Please can you put pin numbers outside the IC 'box' and the signal names inside, alongside each connection. Otherwise people would have to find a datasheet to understand the schematic and they won't, I'm afraid. Thanks. | |
| Jun 6, 2017 at 15:54 | history | asked | Mark Colan | CC BY-SA 3.0 |