hello, I have it checked.
a few things -
you have used display with common cathod but needed - common anode.
resistor R1 value is to high - reduce it down to 50..60 ohm or keep the 100 ohm but reduce the ON carrent of LED display,
unfortunately you did not read data of the U2 - 7447 - carefully - pins 3.4.5 should be in High condition( connected to +5 v through resistor 10 kohm f.e),
I hope it helps
thank you for your reply 🙂
but i follow the changing you told me,but it also can't work. Can u help mecheck what is the problem?thank a lot!
yours LCD display is still Common Cathode, but should be Common Anode as I recommended.
fix it and it gonna be OK
Thank you very much,it can work already
if i want add LED and buzzer in to my circuit,have any suggest?
hello, I am glad it helped.
to your questions -
please formulate exactly what you are trying to do.
I am not the admin of this forum, but PLEASE do not forget that this forum is dedicated to discussions about problems using Ultiboard and Multisim, NOT problems how to design a circuit. There are lots of forums and newsgroups on the web dedicated to circuit design problems.