Whew. After one long, exasperating day and a whole morning of fulfilling none of my scheduled tasks...

I found it--this forum on electronics--one thing that has always tired me out and gotten on my nerves. I have no idea as to whether this will solve any of my problems and finally help this desperate soul take that practical test which my teacher will definitely not allowed me to take until my group completes this simple LDR circuit which we have spent almost one month assembling--all to no avail.

SIMPLE, isn't it? Indeed, it is. For a student in a science high school with so many requirements to do and subjects all willing to kill--algebra, chemistry, computer science (my favorite science&tech-related subject--I do quite well in it; however, all that HTML encoding takes up so much time), earth science, english (the Science of the English Language and its Several Sub-branches, I would call it) fil, social sciences (all that memorizing will get me dead, all the other sciences (since enumerating each and every one of them would steal so many precious seconds from my limited time), and finally, TECHPREP--Technology Preparation--the subject where BASIC ELECTRONICS is taught.

Now, in order to get my grade for this final quarter, I must be able to build an LDR circuit on a breadboard provided by our teacher with the following five components:

1. Battery
2. LED (Light-Emitting Diode)
3. Potentiometer
4. Transistor
5. LDR (Light-Dependent Resistor)

I have made it already with four of these components. Below is a diagram and some pictures of the circuit I have succeeded in building:

http://i254.photobucket.com/albums/h...shake/scan.jpg
(Pics to come)

As you see we lack an LDR--we can't seem to figure out where to place it and how to put it in. We've tried every single LDR available, but no matter what we do, we can't seem to get the desired effect: when LDR is covered, the LED must shut off and not emit any light. Instead, nothing happens; the circuit remains as it is. The LED does not shut off nor dim when the LDR is covered; only the potentiometer can control the brightness of the light it emits. I've tried installing other components such as switches and buzzers, and they worked properly. What do you suppose is wrong then?

How do I install the LDR on the breadboard to make it work? If you could explain it using my diagram, it would be very much appreciated.

 

http://www.uoguelph.ca/~antoon/circ/actrelay.htm

Replace the relay and diode with your LED, suggest a series resistor, so you get more then a single bright flash ... Since you had to ask figure I should also mention, that LED should be installed in the opposite direction of the diode in the schematic, which was there for protection.

How come you didn't just search the web for the circuit (like I did), there many others, this was just the first one...

 

The circuit you're attached doesn't mean anything to me.

Please draw it using the propper symbols rather than just how you plan to lay it out on the breadboard.

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Hello there.

Pardon me for making a very sloppy diagram...

I'm actually a beginner in this field... as of now I don't even think I have any plans to pursue it, though I really must get the grade.

The setup was given to us by our teacher and I think we have to follow it. A sample was made available to all of us; however, it was on a different kind of breadboard and I don't suppose we can ask our teacher about this--we're supposed to learn on our own. It's stressful, really.

I posted the same problem on another forum and it was mentioned that there might be a problem with the resistor. I'm not sure. This is where all the electronics experts are so this is where I'd like to confirm.

 

You cant expect to get help when you dont really want to learn, you just want others to do your project for you.

W/o a meaningful diagram, and with your cryptic explanation, your request is utterly un-answerable!

Look up LDR circuits on google, then if you still have problems understanding, post again, but this time be sure to include a good schem, or to reference a webpage that you have problem understanding.

The first stop, before any forum positing should be google.
The first thing that comes up in google when i type "LDR circuit" is http://www.doctronics.co.uk/ldr_sensors.htm. this should explain the ldr circuit.

 

So where's the "Immediate Rescue Job"?
I'll send the 'Thunderbirds

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com

 

http://www.technologystudent.com/elec1/ldr1.htm

Please read that , study it learn it. Thats a freeb from a noob. even i know how to search. You need to really try to actually succeed.

 

All right, thanks. Followed the links you posted. I'll try to assemble the circuit with the info there...

 

We are not trying to say that we wont help, you just have to show interest. If you get stuck, im sure that the good people of this forum will endevour to help you.