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where can I find a truth table so I can see what should be on when.
Just google 'BCD truth table' and you'll find several.
 
I dont understand why 2 only are coming on and not the third they all have the same Resistor

Are you still using series 10K resistors with your LEDs.? the different colours have different forward voltages.
 
I am using all the same Red LED's

OK,
If you look at the top plot in post #2, it shows the sequence how the LED's are lit.

Recheck your wiring against that post #2 circuit, it works in simulation.
 
The datasheet for the4029 shows only approx 2mA at a 12V supply.
I do not know where you found such low output current.
Texas Instruments shows graphs for the output current of all of their Cmos logic ICs. With a 12V supply, one output can drive a red LED with typically 19mA and can drive a blue one with 18mA. The minimum output current is half these currents.
The current-limiting resistor values can be low enough so that the LEDs are bright but the IC does not get too hot.

EDIT: I see that if the LED has a forward voltage of 11.5V (but it doesn't) then the current into it is very low.
 

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I will do that. Can you suggest software for simulation.
I do not know if any simulation software has accurate models for Cmos logic output current.
Simply build the circuit and test it.
 
I will do that. Can you suggest software for simulation.

hi,
If you sign up here, free, **broken link removed**

You can download LTSpice and have access to all the library models for the CD series of CMOS logic

EDIT:


Rodney, as you have now removed the drive transistors and connected the LED anodes to +12v, the output logic will be inverted..

So the LED's will be ON when the 4029 outputs are low, which is NOT what you want.

Eric
 
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I do not know if any simulation software has accurate models for Cmos logic output current.
Simply build the circuit and test it.

The circuit has already been built by the OP and it does not work, his circuit diagram looks correct.

I ran a simulation in LTSpice in order to show the OP the waveforms.
 
Thank you for all your assistance I have certainly learnt alot with all the advice. I found a small bridge that was not letting the output of pin 14 go high or low. Once removed the circuit worked exactly as explained. The outputs were inverted makng a truth table tricky, however I will put the transistors in for switchng now.

Putting the capacitors onto the base of the transistors will this allow the colours to fade into each other.

I have also put the tri colour LED into the circuit Blue and Green Very dominant. If I was to put larger resistors in for the Blue and Green would this bring all the colours to similar intensity.

Again THANK YOU for all the help
 
I have also put the tri colour LED into the circuit Blue and Green Very dominant. If I was to put larger resistors in for the Blue and Green would this bring all the colours to similar intensity.

Again THANK YOU for all the help

hi,
Increasing the series resistor values will reduce the LED current and their light output.

E.
 
Modern blue LEDs are much brighter than red ones. Modern green LEDs are made with the same material as blue ones so they are also very bright and have the same 3.3V to 3.6V forward voltage of the blue ones and not like the 2.2V of old dim green LEDs.

My tri-colour solar garden lights have very bright blue and green but the red is not bright.
 
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