I am about as new to electronics as you can be. So bear with me.
I am trying to do a very simple LED circuit for a nightlight, using a Photocell to turn it on at night and off in the daylight. I found the circuit on the instructables forum and want something VERY simple. I do not care if it goes on when it is dim in the room, or when it is cloudy (i want some differentiation, but I am not picky).
THe instructables I looked at is here:
http://www.instructables.com/id/Blue-Bawls-automatic-LED-light/
I got the same parts he lists:
9 Volt Battery
Photo-Cell
NPN Transistor (2N 4401)
Super Bright White LED
100K ohms Resistor
470 ohms Resistor
9 Volt battery Snap
Except I want to run this of of a Wall Wart, and have been using a 12volt source on my breadboard.
I wire it up to match his breadboarding and it does not work. The LED comes on, but the Photo Cell does nothing to effect it. I have tried 2 different photocells that i got from All Electronics (smaller physically than his) and I get nothing.
I am trying to figure out whether i am messing up the breadboard work, or the wrong photocells.
Here are some Pics. I apologize, they could be sharper, but they show the circuit:
The fullsize images are here:
http://www.jklinephd.com/photoled1.jpg
http://www.jklinephd.com/photoled2.jpg
http://www.jklinephd.com/photoled3.jpg
The photocells came from jameco and here are the stats:
PHOTOCELL,90mW,150V PEAK,
27KohmMAX LIGHT,2MohmMIN DARK Jameco#:120310
PHOTOCELL,90mW,150VPK,5Kohm,
MAX LITE,20Mohm MIN DARK Jameco#:202391
PHOTOCELL,150mW,200VPK,3.6Kohm
MAX LITE,0.3Mohm MIN DARK Jameco#:202438
Suggestions? Errors I have made?
Thanks
Jeff
I am trying to do a very simple LED circuit for a nightlight, using a Photocell to turn it on at night and off in the daylight. I found the circuit on the instructables forum and want something VERY simple. I do not care if it goes on when it is dim in the room, or when it is cloudy (i want some differentiation, but I am not picky).
THe instructables I looked at is here:
http://www.instructables.com/id/Blue-Bawls-automatic-LED-light/
I got the same parts he lists:
9 Volt Battery
Photo-Cell
NPN Transistor (2N 4401)
Super Bright White LED
100K ohms Resistor
470 ohms Resistor
9 Volt battery Snap
Except I want to run this of of a Wall Wart, and have been using a 12volt source on my breadboard.
I wire it up to match his breadboarding and it does not work. The LED comes on, but the Photo Cell does nothing to effect it. I have tried 2 different photocells that i got from All Electronics (smaller physically than his) and I get nothing.
I am trying to figure out whether i am messing up the breadboard work, or the wrong photocells.
Here are some Pics. I apologize, they could be sharper, but they show the circuit:
The fullsize images are here:
http://www.jklinephd.com/photoled1.jpg
http://www.jklinephd.com/photoled2.jpg
http://www.jklinephd.com/photoled3.jpg
The photocells came from jameco and here are the stats:
PHOTOCELL,90mW,150V PEAK,
27KohmMAX LIGHT,2MohmMIN DARK Jameco#:120310
PHOTOCELL,90mW,150VPK,5Kohm,
MAX LITE,20Mohm MIN DARK Jameco#:202391
PHOTOCELL,150mW,200VPK,3.6Kohm
MAX LITE,0.3Mohm MIN DARK Jameco#:202438
Suggestions? Errors I have made?
Thanks
Jeff