The output of a photodiode primarily consists of output current, which varies based on illumination and is specified in the device's datasheet. Photodiodes do not have a defined output voltage unless they are reverse-biased by an external voltage. The maximum photocurrent can reach up to 50mA for some models, but this varies widely among different photodiodes. For detailed characteristics and output data, users are encouraged to consult manufacturer datasheets and distributor websites like digikey.com. Understanding these specifications is crucial for proper measurement and application of photodiodes.