This video explains "How to design a photodiode amplifier circuit" in two different circuit implementations: photoconductive mode and photovoltaic mode. This features Microchip’s MCP6491 low input bias current op amps, the characteristics of photodiodes, and the strengths of the active photodiode current-to-voltage converter (i.e. photodiode amplifier). It utilizes a 5V power supply, inputs 0-50 microamps, and outputs a 300mV to 2.7 volts. The focus shifts to the design techniques of photodiode amplifier circuitry. Several key design points are discussed in order to improve the circuit’s performance depending on the application. This is the second video of a series of videos on Photodiodes: Microchip's Solutions for Light Sensing Applications. Photodiodes: Microchip's Solution for Light Sensing Applications Playlist: https://www.youtube.com/playlist?list=PLtQdQmNK_0DS4jspKPincFaxeg1VKqkw9