which wire is the 12 volt on molex???

[shocksyde]

i'm making a baybus and when i tried attaching it to the molex to test it, nothin happened. i attached it to the yellow wire, isnt that the 12 volt one? or is the red one?

also, i was using an old power supply in an old computer case to try and test it. its different than my current computer in the sense that the power supply fan will turn on even if there isnt a mobo in the case. the on switch on the case goes directly to the power supply. does this mean that i can test my baybus on this power supply or do i have to have a mobo in there???

thanks,
shock

[flash4master]

yellow is the +12

[shocksyde]

also, will an LED work without being attached to a ground? if not, how do i ground it? just attach the open end of it to one of the black wires from the molex?

shock

[Roy]

Hello, again! How goes the project?

Both leads of a LED must be connected. The black wires both are "ground". The shorter lead on a LED is "minus" or ground. I hope you are using a resistor to limit the current to no more than 20mA.

Older "AT" supplies put out without a mobo. An automotive lamp ~ instrument panel or tail light, for example ~ is a handy item for finding out if 12V is present.

[This message has been edited by Roy (edited 12-01-2000).]

[Graham]

Shock,
You will need to ground one leg of the led, you must have a resistor in series with it (conventionally in the + line, but either will do), as they are not 12V devices.
Most leds need about 1.5V across them, some need as much as 5.5V.
If you are using the 12V supply, the value of the resistor can be calculated as follows...

Assuming the led's need 20mA (common red ones)


R=V/I =12/0.02 =600 ohms (560 and 680 are standard values)

If you want blue !!(just a guess) then they need more cuurent, perhaps 40mA

12/0.04 =300 ohms (270 and 330 are standard value)

You connect like this

+12V to resistor to LED to 0V

They are polarity sensitive, once you have the resistors added then you can put them across a 9V battery to check which side is positive.

G

[shocksyde]

well my dad got home and he was an engineering major in college so he helped me. let me just say that these blue LEDs from radio shack are about as bright as high beam headlights...they rock!!! great accent to my blue neon! this is too much fun...

i see myself adding infinite blue leds to my case http://sysopt.earthweb.com/forum/smile.gif

EDIT: oh hey roy, well this is actually a seperate project than the one i was talking to you about. however, i still need your help for my next project! the modding never stops once you start...makes me wish i had saved up for a car instead of pumping all my cash into my comp!

shock

[This message has been edited by shocksyde (edited 12-01-2000).]