hi ,
i am working on a project and i need some help. well the main idea is to detect red light( from laser pointer) through a photo transistor. anyways, i need a circuit for the transistor and i need to know how to calculate the resistance needed etc...


thanks in advance

 

We need a little more info:
What is the part number of the transistor?
What is the circuit you want to turn on?
what voltage do you want to use?
With this info we can probably come up with something...

 

check out this thread.... laser activated target.... >> http://forum.allaboutcircuits.com/showthread.php?t=33549

B. Morse