need the output of the shematic

[senthil_var2000]

as i ahve got the circui from one of the web site for free and i made the circuit in gemeral pcb by my self as per the circuit specification .i am getting the output from ic4017 correctly but after that drivrs are not working properly the transister are getting heated can any one tell me what colud be wrong . the transistor t1 was the first heat tranistor so as the t2,t3,t4... .And another one problem is only one led coloum is glowing and rest is in off position even when i increased the voltage the respective sequence of light is not working properly. i need to get the out put like this
W
WE
WEL
WELC
WELCO
WELCOME

BUT I AM GETTING
W
E
L
C
O
M
E
ONLY ONE OUT PUT AT A TIME

plz tell what is the problem and i am using 6 v 750ma transformer.
**broken link removed****broken link removed****broken link removed**

 

[audioguru]

Hi Senthil,
You seem to have many LEDs in parallel for each letter so their brightness levels are different, you don't have any current-limiting resistors for the LEDs and your cascaded voltage levels don't work:

 

[senthil_var2000]

what is to done

from the above i understood what is the problem plz tell me the correct circuit

 

[audioguru]

1) You have 99 LEDs. When they are all turned on, if they are fairly bright at 25mA each, then the total current is 2.5A!
2) You could use a 12V supply, and if the LEDs are 2V red ones, you could wire 5 in series with a current-limiting resistor. Then you would have 20 strings which would draw only 475mA when they are all on and bright, and they will all be at the same brightness.
3) Connect a small NPN transistor to each output of the 4017 as emitter-followers, then they will provide enough current for the many diodes.
4) Use the power transistors as common-emitter, with the strings of LEDs at their collectors. Then they won't heat because they will saturate when turned on.

 

[senthil_var2000]

working with all interconected

but the whole circuit works brightly in a 6v 750ma transformer when all are interconneted that is parallel can i use the same instead for 9v 2.5a transformer

 

[audioguru]

Leds are rated for a max current of 30mA each. Usually they are used at 20mA. If your 475mA transformer isn't severely overloaded then each of your paralleled LEDs operates at only 4.8mA which is not very bright.

If you use a 9V, 2.5A transformer then something will burn, probably the transistors.

If your LEDs are 2V red ones, then with a 9V supply the transistors must throw away 7V as heat. If the LEDs are wired in series then they get the power instead of the transistors. Also, with them in series, much less supply current is needed. With a 9VDC supply, you could have strings of three 2V red LEDs in series and in series with a current-limiting resistor.

 

[thisistausif]

the ic 4017 gives only one output high at a time

u can use caps to store ..

 

[audioguru]

the ic 4017 gives only one output high at a time

u can use caps to store ..

But the diodes activate the driver transistors for the other letters.
Caps might discharge too soon.