• State
  • Locked Locked
  • Replies 0 replies
  • Subscribers 62 subscribers
  • Views 252 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Calculate number of outputs SN74LS138

Abel Valero
Prodigy 230 points
Other Parts Discussed in Thread: SN74LS138

Hi everybody,

I have a question regarding full color displays. As you know, normally to select the active line in LED displays we use a demultiplexer (SN74LS138) for example which outputs are connected to MOSFETs that works as a switch.

My question is how can I know or calculate the number of MOSFET's that I can connect to each demultiplexer output?

For example for a 32x16 (WxH) rgb matrix normally if I'm using 1/8 scan I connect this way:

- Y0 (first output of the demultiplexer) to MOSFET line 1 and MOSFET line 9

....

- Y7 (last output of the demultiplexer) to MOSFET line 8 and MOSFET line 16

What if I'm using 1/4 or 1/2 scan?

Thanks in advance