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Lil Help Please

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Twisted1

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Hey guys, i hail from sunny s.a

im a newbie to this forum and to electronics as a whole, have a small prob, and its annoying me coz i dont know what i did wrong. im using multisim 10 at the moment. i just have to keep a light on for '9' seconds using a 555 timer and a 74x163 counter but its just not working right. please help, i attached two pictures, one is a schematic from multisim and the other a truth table that i have to use, the "*" on the truth table is the dont care conditions.
Im using karnaugh minimizer pro aswel

any help on my connections or just telling wat the hell i did wrong will help!!!

thanks guys for any help!
 

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lil help, added

jus attached the multisim file if u guys want to play around, sorry i didnt attach before!! (oops just saw i cudnt upload it, sorry again!)
 
Last edited:
The LED or light bulb is not connected to ground nor to the 5V supply so it will never light.
The 74HC05 has open-drain outputs so their outputs will never go high. Use a 74HC04 IC instead.
 
lil help

its just a probe light, and it does light up when it feels like it. as for the
74HC04 i will def give it a try now, i thought its just an inverter? i just wanted the output from the counter to be inverted as per my circuit needs. thanks man, il try it out now. This design will be built on bread board first and the it WILL be put on pcb. and warnings or families of chips i should stay away from so that i dont get errors wen i do build it?
 
nope even with the 74HC04 inverters its still not workin. can someone tell me if my counter is set up right? im pulling my hair out! i even connected up a 5v 1w bulb and grounded it and it come son and off wen it feels like, pls some1 help
 
What limits the current to the LED or to the light bulb?
If you have nothing limiting the current to the 25mA max allowed output from the 74HC00 then it might be destroyed. A 5V/1W light bulb tries to draw 2000mA when cool and draws 200mA continuously when hot. The poor 74HC00 will try to drive it with about 50mA and will be killed.
 
Dearly beloveded

we are gathered here today to bury a 74hc00 ic chip
it gave its life for the furtre advancement of electronics
couldn't resist
 
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