Photodiodes, light-induced electron

If a charged condenser is connected in parallel to a photodiode, electrons will flow away from the N-layer into the condenser anode, while electrons from the condenser will compensate the hole excess in the P-layer. As a consequence, the condenser is discharged. The discharge of the capacitor through the photodiode will be proportional to the light intensity inducing the N-P layer junction polarization (Figure 6). 

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