[SOLVED] How to change from 74LS48 to 74LS47 on circuti

[dadili]

I have this circuit as counter https://i.imgur.com/rUm7M.jpg
how to replace 74LS48 to 74LS47 so it works the same, count from 0-99

 

[mister_rf]

Try this way:

 

[HTA]

Why you want to change? The LS48 is identical with the LS47 except for the driver capability on the output and the LS48 has an internal pull up. The LS47 has a 24mA sink current capability, while the LS47 has only 6mA! Thus using 330 ohm would overload the output drive. The datasheet is here: https://www.ti.com/lit/ds/symlink/sn74ls47.pdf .

 

[mister_rf]

Need to read more carefully the datasheet.

 

[dadili]

I can't find 7448 component to buy

 

[mister_rf]

Use the 74LS47 with the modifications I have suggested (this must include also the RESET button) . The 74LS47 series can handle the required LEDs current .

 

[dadili]

I will thank you.

 

[mister_rf]

Minor modifications in the schematics to access RESET function.

 

[dadili]

yes, that worked thank you very much for your help