Is there a difference in Voltage/current read in these 2 phototransistor circuits.

Thread Starter


Joined May 29, 2017
Hello, i'm writing a project on a line following robot, and i have this Phototransistor sensor that works different from other i've read about.
I'm using a QRE1113 Sensor

From what i can read from this site; , the sensor should output higher current/voltage when more light is shone into it, but my sensor outputs LESS, when light is shone into it.

Could it be because of the way the circuit is set up?
My circuit looks like this upload_2017-5-29_13-51-16.png

and the circuit from the 2nd site looks like this

So as you can see, the Resistor in my circuit is tied to VCC and in the other circuit it's connected to ground.
Thanks in advance, i hope this wasn't an all too confusingly put question.
The phototransistor output current is increased as more ight is applied. The voltage drop across the resistor is higher as a result of the increased current. The rest is a matter of how the circuit is connected.