I'm projecting a light follower robot, and I planning to use two voltage dividers, each one composed by two phototransistors and two protective resistors in series (in a sequence R - Pt - Sensing node - R - Pt). The middle node is to be connected to two comparators. The objective is to compare the light hitting each phototransistor. I'm using two dividers, one to compare front/back and one to compare left/right. Additional logic will be included. Originally I was using LDRs, but the guys from E.U. are taking them from the market (a stupid decision).
So, my question is, what is the maximum current that a phototransistor can handle for safety and maximum lifespan? Should I consider the same for a LED (20mA)?
I'm asking this because I pointed a phototransistor in direct sunlight, and the current reached a stunning value of 46mA. The phototranstor heated noticeably. I just don't want my project to auto-smoke in the sunlight like a vampire.
I'm using L-7113P3C from kingbright (available in Europe): http://www.kingbright.com/manager/upload/pdf/L-7113P3C(V4).pdf
So, my question is, what is the maximum current that a phototransistor can handle for safety and maximum lifespan? Should I consider the same for a LED (20mA)?
I'm asking this because I pointed a phototransistor in direct sunlight, and the current reached a stunning value of 46mA. The phototranstor heated noticeably. I just don't want my project to auto-smoke in the sunlight like a vampire.
I'm using L-7113P3C from kingbright (available in Europe): http://www.kingbright.com/manager/upload/pdf/L-7113P3C(V4).pdf