Okay, it all arrived this morning, and now I'm playing with it, look at the LED's go! (didn't blew anything up yet, guess I'm not that kinda noob after all ). Anyway, I also bought a photo-resistor, but it increases its resistance when the lights go out. I'm searching for a way to "invert" that, so that the LED's will go on when the light is out. I tried a not-gate, but fortunatly for me I looked at the datasheet and the max voltage input is very low, as is the max power (10ma). So I guess I'll need to do something about that using a transistor or something, but as I'm a n00b I really don't know how to start with it. So, my question is, can anyone tell me how to "invert" the resistance of the photoresistor? I have all kinds of resistors, capacitors, transistors, NOT, AND, OR-gates, ... except for diodes (normal ones), I don't have any diodes Thanks
put the thermistor in a voltage divider. I assume you want the voltage across to drop as the temperature increases, no? You can't really do anything directly with resistance in a circuit in terms of triggering stuff, you have to rely on the voltage across the resistors g
With +supply-resistor-LDR-ground, the voltage at the bottom end of the resistor will go down as light goes up. Feed the level into an op-amp or comparator, and compare with a potential divider voltage to switch a led. Swap the resistor and LDR for more volts at more light.
Throw it away and buy a phototransistor. Some bozo wrote an introductory article to logic gates, but never got around to writing all the rest of the stuff you need to know about digital design.
