H Exp – Radiation and Matter 12 – Photodiode – photovoltaic mode

Aim – To measure the frequency of an a.c. suppply using a photodiode in photovoltaic mode.

Instructions

The photodiode is placed near a 12 V lamp which is connected to an a.c. supply.
The y shift on the oscilloscope has been adjusted to produce the trace shown.

The y- gain and time base are increased by clicking on the right side of the knob.
They are decreased by clicking on the left side of the knob.

▪ Adjust the y gain and the time base to obtain a clear trace.
▪ Calculate the frequency of the a.c. supply from the trace produced. (Remember that the intensity of the lamp peaks twice for each cycle of the a.c. supply)