transistor pinout

daguuy · Post by **daguuy** » Sat Dec 24, 2005 3:03 pm

i found a site that tells what a transistor does and how to use it so i might be able to make an amp but that site says the pinout for transistors is CBE but the labels on my transistors on some old junk i found say BCE. are my transistors wierd or is that site wrong?

Post by **gannon** » Sat Dec 24, 2005 9:22 pm

IIRC it's different for PNP and NPN

daguuy · Post by **daguuy** » Sat Dec 24, 2005 10:43 pm

OK thanks. i just got an idea! my big TV has a crappy VCR for connecting stuff to. the VCR messes up the video from DVD players but it works when i connect the DVD player directly to the TV. i'm getting kinda tired of switching the video between DVD and VCR so i decided to make something to do it for me automatically so i don't need a switch. would this diagram work for that? what it's supposed to do is connect the video source when it's on but disconnect it when it's off

do i need to caps? if so, did i do it right?

timmeh87 · Post by **timmeh87** » Sat Dec 24, 2005 11:10 pm

even some transistors of the same type have different pinouts.

is there a problem with having two things plugged into the same video in, but only one outputting video? like, cant you just get a Y cable, and connect them both at the same time?

anyhow, i have no idea if that circuit will work. did you base it on anything or did you just sorta make it up?. is a video signal strong enough to drive a transistor? i know with MOSFETS, if you open them up, they dont close again untill you supply the opposite voltage. if you just turn the power off, they "float" so to speak, and will remain on.

(actually, isnt a video signal AC? so wouldnt that rapidly switch the transistor on and off?)

Post by **gannon** » Sat Dec 24, 2005 11:34 pm

no, video is DC.
Anyways, just use a Y connector, with that circuit if both units are powered on it'll still mix the signals.

timmeh87 · Post by **timmeh87** » Sun Dec 25, 2005 11:54 am

analog video is AC

anatomy of a video signal

the data itself is DC, so to speak, but the sync pulses are -.3v

Post by **gannon** » Sun Dec 25, 2005 5:28 pm

or more accurately

floating (AC-coupled) video signal