controlling equipments using the computer................

hello!

just want to ask some questons


why do we have to use IC's such as an 74ls374 in controlling equipments using the computer?

can't we control DC equipments directly from the computer using only the parallel port and a transistor?


thanks!!

It depends on what you are driving, but it is done for security reasons, you don't want to loose a port on your PC for a short or mistake on the other side. If you try to pull to much current out of the port you will damage it. So to avoid those problems you use a chip. Yes you could use transistors, but by the time you have all the biasing components for all the lines in the parallel port, you use a lot of space and time putting in together. Why not just use a chip instead? There are plenty more chips that can be used instead of the 74ls374 it is all upto you.

Ivancho

So you are 1/2 way through a days testing and suddenly BSOD

say no more...

thanks for the replies. it helped a lot .

i've got another question:

we're planning to use a PIPO register made of D FF as the ICs connected to the parallel port. the outputs of this are connected to a transistor. the transistors are the one connected to the equipments we are planning to control.

is this set-up okay?


and what BSOD?


thanks..........

thanks for the replies. it helped a lot .

i've got another question:

we're planning to use a PIPO register made of D FF as the ICs connected to the parallel port. the outputs of this are connected to transistors. The transistors are the one connected to the equipments we are planning to control.

is this set-up okay?


and what's BSOD?


thanks..........

BSOD is blue screen of death. This happens wen you eject a floppy disk while it is being read, microsoft displays this blue screen. Theres other ways to get a BSOD but yeah...

Check this out:

The 8Way Relay Board
https://www.electronics-lab.com/projects/pc/005/index.html