Alright - Im feeling real dumb...... i did something wrong... its not working

=(

Im starting a new one

 

I need to give up electronics/....... I cannot seem to get this right.... It still doesnt work.

My LED is a 2.6V, 28 mA, 10 mcd.... is that the problem ?

 

Possibly, you may also want to consider stepping down the voltage to about 3v, If you have an adjustable power supply, drop the volatage to 3V then test the LED alone, you could have easily blown it, I know I've popped a whole lot of them.

Also if you still have any of the packages make sure none of them say "Bi Polar" if not, one by one flip everything but the transistor, (save this one for last) and test each different position, after you test one, flip it back and try the next.

It's very easy to miss this one.

But I'd first try testing the LED, if it comes on, check all your connections, make sure you didn't do something trivial like connecting a resistor horizontally on your breadboard.

 

I just took a long hard look at your schematic, and two things didn't seem right, the placement of the transistor, and the positioning of the LED.

For some reason the transistor just doesn't look right, I have no idea why, and consider moving the resistor and LED to before the probes.

 

What ya mean hooking it up horizontally ??

I cant find anything that says bi-polar...

What color bands are on a 1K resistor...

By the way - all resistors are 1/4 watt

 

led works......

Im not usin a bread board - sodered it up on a little board from Radio shack...

 

okay, well then I guess my first Idea wouldn't matter... hooking up a component on a breadboard horizontally is a no-no, it'd be like making a PCB with wiring like this ---0----0--- and we all know that doesn't work

anyway, just keep messing with it, and 1K is Brown/Black/Red fourth stripe is the tolerance if yours has one, if not, doesn't matter.

 

Looking at the transistor from the TOP-its shaped like a D right... So, you hold it looking at the top so the arc is too the right or as the letter D is written, the Emmiter wire would be thetop wire correct ?? The Middle is the base obviously, and the collector would be the bottom wire...... Im just makin sure I didnt hook up the transistor backwards... if I did would it have blown the transistor ?? I am using a 9 volt battery by the way -

 

No, it wouldn't have blown the transistor, but it wouldn't work right, the emmiter should be going toward negative, so try reversing the transistor.

 

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Attached Images

	H2OLED0.jpg (30.8 KB, 1749 views)
	H2OLED1.jpg (54.7 KB, 1744 views)

 

Mofset.... whats a common mistake I may be making ??

 

If You make a shortcut between electrodes it work?

 

GOT IT !!!!!!!!

i got it working..... works perfect for what I need.... now i have to put it on my caliper configuration.....
THANKS GUYS !!!!!!!!

I appreciate the help

 

okay, what was wrong ?

 

as far as i can figure, i must have had the trasistior wrong