How do you use the decoder? I mean I tried connecting the vcc and ground to its respective connections.

Connected rbi rbo and lt to supply 5 v

And connected outputs to 7 seg.

But it doesnt work. Tried using switches and connecting the input pins to ground or supply. Had no problems in 7447.

P.S. already checked data sheet but I just dont understand how to make it work.

 

Show your drawing on how you connected it ... or take a picture of your breadboard.

 

Or is it possibile that I use CA? Nah used vom to check. Connected negative tester to gnd of 7 seg and used the positive to check the segments.

When i connect lt to ground the seg all lights up.

 

Show your drawing on how you connected it ... or take a picture of your breadboard.

Ok i'll show it. Not at home atm sry.

 

Or is it possibile that I use CA? Nah used vom to check. Connected negative tester to gnd of 7 seg and used the positive to check the segments.

When i connect lt to ground the seg all lights up.

Does this confirm your question about it "possible that I use CA?"

Here's a tutorial.

 

Does this confirm your question about it "possible that I use CA?"

Here's a tutorial.

I'm sure I am using Common cathode. Just tought of it because it doesnt work.

I've attached the schem. I know it should work but it doesn't. I am also using a larger 7 segment 1 inch width.

 

You need common anode displays for use with the 74LS47 and common cathode displays for use with the 74LS48.

Les.

 

Did you look at the truth tables for each?

Look and see what you need or can use to make it work properly with what you have.

 

You need common anode displays for use with the 74LS47 and common cathode displays for use with the 74LS48.

Les.

Yes I used 7448 with common cathode.

Did you look at the truth tables for each?

Look and see what you need or can use to make it work properly with what you have.

I've figured out what's wrong. I need to supply 5 V to pin 3 and 4 ONLY. (LT and RBO) while I need to connect pin 5 (RBI) to the ground. It worked as it is supposed to now.

I don't really understand. In Common anode/7447 applying 5 V to pins 3-5 would work.

Anyway thanks!

 

I don't really understand. In Common anode/7447 applying 5 V to pins 3-5 would work.

Aside from the outputs being the opposite polarity, the function tables for 7447 and 7448 are the same.

 

I don't think it worked as you built it ....