Patent ID: 7022967

Claim:
A photodetector comprising: an operational amplifier having an inverting terminal and an output terminal; a photodiode connected to the inverting terminal of the operational amplifier for outputting a signal corresponding to a quantity of light to be detected; a plurality of feedback resistors, each being differentiated in resistance value, one of said feedback resistors having a maximum resistance value and being coupled between the inverting terminal and the output terminal of the operational amplifier; a first analog switch for selectively connecting one end of each feedback resistor, other than the resistor having a maximum resistance value, to an input terminal and connecting the other end to the output terminal of the operational amplifier; and a second analog switch that is used for selecting at least among (1) the output terminal of the operational amplifier, and (2) an end of one of the plurality of feedback resistors to externally output an output voltage, wherein the other ends of the other feedback resistors are connected to the inverting input terminal of the operational amplifier.