Hi,

I'm trying to measure the duration of a light pulse in the μs range, I purchased a BPW34 photodiode for the task (is this the best choice?). In photovoltaic mode (used as a solar cell) it gives readings of about 10x longer duration then it should. Here I'm just connecting the scope to the diode and flashing the light on it.

So, now I want to try use it in photoconductive mode to increase the response time, the diode itself has listed rise/fall times of 100ns which should be good enough. Supposedly I have to provide "reverse bias" to the diode. Can anyone help me design the circuit to measure the light pulse?

 

Photo transistor might be easier, but not as fast. But here is an app note on diodes. Hope it helps.

http://www.ti.com/lit/an/sboa061/sboa061.pdf