DIGIT-ARC read-only archive · snapshot: July 23, 2026

Dilemma in connecting Parellel Port to a light bulb

5 posts · originally from https://geek.digit.in/community/threads/dilemma-in-connecting-parellel-port-to-a-light-bulb.19959/

F
Febians Original post #1
Dec 7, 2005 at 7:31 PM
Hey guys,

Could you plz guide me on how to connect a bulb to the data pins of the parellel port so as to not spoil the port. (using it on a laptop, so)

I'm not from an electronics background so plz guide in layman terms.

Help!! pl.
L
LordDJ #2
Dec 7, 2005 at 11:48 PM
First things first. Playing around there if you aren't too aware of what you are doing could damage the port.

Secondly connceting a "bulb" is not feasible as the port won't be able supply that much power. However you can use an LED. But just sticking an LED won't make it light. You've to turn on that pin (this is very very layman's terms). This requires that you write some code.

If you've got some free time on hand and want to impress your friends, it's nice. There's a book ny Jan Axelson on parallel port programming. It's interesting. Give it a go. Otherwise ask any electronics engineers around to do it. Hardly takes an hour.
F
Febians #3
Dec 8, 2005 at 10:28 AM
Hey

Well i've got the code ready. Have even lit the LED lights looking at some tutorials online. I know the port supplies less power then required to lit a bulb.

The plan is to have the ||port controlling whether the circuit is closed or not...
I got the ONLY book from british library here in bangalore on ||port programming. But it recommended buying some specialized breadboard. I wanted to do the whole thing on my own.

I'd defi try to find out abt the book. Meanwhile, any further help would be appreciated.

Thanks
ps: Going to use C for now. But have got some sample codes from VB too. I am fairly good with C but not with VB. So the coding part is taken care of.
lywyre
lywyre #4
Dec 8, 2005 at 10:41 AM
so what r u going to light an LED for

may be, like this "light music" *members.cox.net/transam57
L
LordDJ #5
Dec 8, 2005 at 6:29 PM
It's quite possible to connect a bulb to the parallel port. But you need a driver transistor for it. Also search for something called optocouplers. Not too difficult to find circuits on the net.

Right now I'm bugged otherwise would've done a gooogle and posted a good link. Sorry. :cry: Anyway do post your status.