You can add more LEDs by adding more transistor drivers similar to the circuits shown using Q1 and Q2.
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.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.
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.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?
I will post the pictures tomorrow. Its NE555.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?
ok thanks.Why do you have pins 2, 5, 7, 9, 12 of the 4017 connected to GND?
Remove these connections. Do not connect unused outputs.
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...
But, when I transferred to a 12 volt power source, my 555 and 4017 IC burned. Any thoughts?
What about 555 ?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 ?
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.
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by Jake Hertz
by Jake Hertz
by Jeff Child