Cmos 4026

[amando96]

Hi, i'm making an electronic clicker, basically just want to press a button to increment the digits by one, and have a reset button as well, something like this:
**broken link removed**
but with buttons, and more digits

anyway, my question is, is this made to be used with common anode, or common cathode 7 seg displays, or configurable for both somehow?

Also, how do i get it to only count up 'till 5, or 6, instead of 10? i have read around, and can't find much info...

thanks

 

[crutschow]

All the info you need is in the data sheet. Have you read it?

The outputs are high when active, but depending upon whether the device is an A or B suffix, the supply voltage, and the required LED current, you may need a buffer driver for each segment (and don't forget the required current-limit resistor in series with each segment). For common-anode (anode to +V) you would use an inverting buffer, and for common-cathode (cathode to common) you would use a non-inverting buffer.

To limit the count to 5 or 6 you will need to add an 8-input AND gate that detects the segment sequence that is high for the desired number, and use the gate output to inhibit or reset the count, as you desire.

 

[Reloadron]

Something else to consider beyond what was covered is as drawn you are likely to have count issues as the "click" switch must be bounce free. Rather than advance a single count with each click, the count will advance several counts.

The counter counts 0 through 9 and that is pretty much that. If you want to count to for example 6 and recycle you would do better to use a programmable counter like the 74192 which will not drive a display directly but will through a display driver chip.

Here is the datasheet link note the section about interfacing with displays as was pointed out. They show examples.

Ron

 

[colin55]

The CD4026 is designed specifically to drive a common cathode display. In fact some of the chips have very good current limiting and drive the segments directly without the need for resistors.
But you need very good debouncing to get the circuit to work.

 

[amando96]

Thanks for the quick replies!
a debounce like this is ok?
**broken link removed**
I'm used to debounce the buttons with software, but i was counting on needing one here.

I read the first few pages of the datasheet, but i was in a hurry to go to work, so i couldn't read it through.

 

[Roff]

That will debouncer clock your circuit when you release the switch. To clock on the leading edge, swap the positions of the switch and resistor.
With a 100k resistor, use a 100nF cap.