I am building a basic night light ordeal, and I used a photoresistor to detect the change in light. Of course, the photoresistor will, by default, only have a high output when there is light, so I used an inverter (Not Gate). My inverter is made up of a transistor , a 1.5k resistor, a 10k resistor, and leads off to a LED. The photoresistor would go off to the Base of the transistor, so it can invert the output. Originally, I had this hooked up to a 4.5 volt input (the photoresistor has 4.5 volts going to it, and the transistor had 4.5 volts going into it), but I wanted to brighten it up, so I upped the voltage to 7.5 volts so I could add a 6.3V Incandescent Flashlight Bulb (http://www.radioshack.com/product/index.jsp?productId=2102809). When I hook this up to a regular 6 volt battery pack, I easily turn the light on. When I connect it to the inverter, however, I don't get anything going on. I've upped the input voltages to 9 Volts, but still, no dice. Everything works fine until I change the LEDs to the bulb. So far, I've changed the resistor values in both directions (I've decreased them down to 10 Ohms, and increased them to a max of 1M Ohms). The only way I can possibly get this to work is by removing the Resistor going to the Collector, but then it is constantly on. The output of the photoresistor no longer matters. The output of the inverter is constantly high. Any ideas? All help is appreciated.