Transistor as switch questions?

Really, seriously, learn to draw schematics. It makes it much clearer, easier for you to notice problems, and easier for people to help you.

Please view the top line of links in my signature.

Thanks for your help everyone, next time I will draw the schematic properly. I will be sure to post my project once completed.

I look forward to seeing it.

BTW, you aren't actually using one of those 9V batteries, are you? They don't have much capacity.

No, I am using a 9V wall power supply.

BTW, you aren't actually using one of those 9V batteries, are you? They don't have much capacity.

9 V PP3 battery

(typical mAh rating = 565 mAh) (56.5 mA for 10 hours, or 113 mA for 5 hours, or 565 mA for 1 hour)

AA cell, 1700mAh to 3000mAh.

http://en.wikipedia.org/wiki/AA_battery

According to Nick Gammon, the Mega 2560 has about 68mA of idle current.

http://www.gammon.com.au/forum/?id=11497

It isn't uncommon for someone writing sketches and trying out different circuits to run them for many hours. Then be taken by surprise when their little 9V battery is dead.

Just making sure he knows...

FYI, you won't get 565mA for one hour out of a 565mAh battery. They rate them -very- generously, at 1/10th or even 1/20th of C, and the capacity goes -way- down when you discharge them at C or faster.

So let's RECAP;

9 V battery = BAD AA battery = GOOD

AA = BETTER

does that about cover it ?

In this case, probably. I was just making sure the OP didn't run into an issue with a dying battery, and end up chasing tales for hours before figuring out that is what was happening.

polymorph: In this case, probably. I was just making sure the OP didn't run into an issue with a dying battery, and end up chasing tales for hours before figuring out that is what was happening.

Isn't "chasing tales" what happens on this discussion board? :D

Hah!

Isn't "chasing tales" what happens on this discussion board?

Among other things... :D