Hi, I'm a new arduino user. I've bought a photodiode (Siemens SFH 205f), and I want to use it as a light sensor. How can I connect it to an Arduino board? Thanks

As long as your looking to detect infrared light then sure. This link may help.

Then, the object that I bought isn't a light sensor, but is an infrared receiver, if I understand.

Infrared is light, just long wavelength light.

Yep, Its a Siemens SFH 205f wide field of view infrared photodiode detector. Here is the data sheet on it.

Data sheet:

If you want light detection then a simple photoresistor is all you need.

Can I connect it like this?