You can add more LEDs by adding more transistor drivers similar to the circuits shown using Q1 and Q2.

 

You can add more LEDs by adding more transistor drivers similar to the circuits shown using Q1 and Q2.

Where will I connect another 2N3904 transistor to? I have a photo below. I added a red line which I thought I will add the new transistor. Please correct me if I have the wrong assumptions.

I noticed that there are unsed pins on the 4017, can I use those to add LEDs also? I'm just wondering.

Thanks for helping.

Jess

 

The output pins of the 4017 where the diodes are connected determine the pattern of the LED flash.

The way they are connected, LED1 and LED2 will flash three times, followed by LED3 and LED4 flashing three times.

R5 and R6 are not required.

Experiment. Build the circuit I described in post #22.
Take the input resistor that feeds the base of the driver transistor and connect the resistor to any output Q0-Q9 and observe when the LED turns on.

You can select any combination to determine when the LED turns on. That is the function of diodes D1-D3.

For additional transistor drivers, include the resistor similar to R3 and R4. Connect the input to the resistor to any Q0-Q9 or any side of the diodes. Experiment.

 

The output pins of the 4017 where the diodes are connected determine the pattern of the LED flash.

The way they are connected, LED3 and LED4 will flash three times, followed by LED1 and LED2 flashing three times.

R5 and R6 are not required.

Experiment. Build the circuit I described in post #22.
Take the input resistor that feeds the base of the driver transistor and connect the resistor to any output Q0-Q9 and observe when the LED turns on.

You can select any combination to determine when the LED turns on. That is the function of diodes D1-D3.

For additional transistor drivers, include the resistor similar to R3 and R4. Connect the input to the resistor to any Q0-Q9 or any side of the diodes. Experiment.

I feel like I'm a complete idiot. Last night when I was experimenting with my circuit I fried my 555 timer. Maybe I have to be more careful next time.

Here is what I did and it fried the 555 timer.



Thanks

Jess

 

If you connected the circuit as shown in the schematic this would not fry the 555.

How do you know that the 555 is bad?

 

If you connected the circuit as shown in the schematic this would not fry the 555.

How do you know that the 555 is bad?

Really? I just removed the added components and when I connected the battery nothing happens except that the 555 is getting very hot seconds after I connected the power.

Thanks

Jess

 

Can you post a photograph of your breadboard before making any adjustments?

Disconnect any wire connected to pin 3 of the 555.
What is the part number of the 555 chip?

 

Can you post a photograph of your breadboard before making any adjustments?

Disconnect any wire connected to pin 3 of the 555.
What is the part number of the 555 chip?

I will post the pictures tomorrow. Its NE555.

 

First of all make sure tht 555 is pulsing by connecting a LED at it's output like I said before

 

MrChips, here's the final working product I have made.



That is working I have tested it and have it connected to a 12 volt power supply for more than 3 hours just to see it doesn't burn itself. But, after I made the experiment I mentioned, the 555 timer heats up and now it's not working anymore.

 

Why do you have pins 2, 5, 7, 9, 12 of the 4017 connected to GND?

Remove these connections. Do not connect unused outputs.

 

Why do you have pins 2, 5, 7, 9, 12 of the 4017 connected to GND?

Remove these connections. Do not connect unused outputs.

ok thanks.

 

MrChips, I have experimented on the circuit as what you have told me. I was able to add 5 blue LED into the circuit and another 5 white led connected to the Q1, Q3, and Q6. They flashes separately. This is when the circuit is connected to a 9 volt battery. But, when I transferred to a 12 volt power source, my 555 and 4017 IC burned. Any thoughts?

Thanks.

Jess

 

Does the power source comes from mains or wall wart?
Is the power source stable.?
Is the power source properly bypassed?

 

...

But, when I transferred to a 12 volt power source, my 555 and 4017 IC burned. Any thoughts?

Thanks.

Jess

With a 12 volt supply the 470 ohm resistors (R3, R4) on the 4017 outputs will allow more than 20ma's current from those and the same to the LED's. That's too much current for a 4017. And the limit for 20ma LED's

Change the output 470 ohm resistors (R3, R4) to 4.7k or 10K
Which version of the 4017 are you using?

 

With a 12 volt supply the 470 ohm resistors (R3, R4) on the 4017 outputs will allow more than 20ma's current from those and the same to the LED's. That's too much current for a 4017. And the limit for 20ma LED's

Change the output 470 ohm resistors (R3, R4) to 4.7k or 10K
Which version of the 4017 are you using?

What about 555 ?

 

What about 555 ?

????
I'm not sure how to respond.
@ R!f@@ I was simply adding my thoughts to your post #54.

 

tubeguy:
My power source comes from a PC power supply which I believe is regulated so I assume I have a stable 12volt power supply.

R!f@@:
My 4017 says its a CD4017BE. Does the version affect the IC behavior?

I will try giving a 4.7k to R3 and R4 and will see what will I get.


Thanks.

Jess

 

Hi archangeljess
Helpers names switched, but you answered the questions.

Yes, the IC variants can make a difference in specs.
A 74HC4017 is specified for a max power supply of 6 VDC, while the CD4017 can handle over 15 VDC.

 

Hi archangeljess
Helpers names switched, but you answered the questions.

Yes, the IC variants can make a difference in specs.
A 74HC4017 is specified for a max power supply of 6 VDC, while the CD4017 can handle over 15 VDC.

Sorry i was confused. I have CD4017.