| Aim - To establish a
relationship between peak and equivalent direct (r.m.s.) values of voltage. |
Instructions |
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- Switch on the left hand lamp.
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- Adjust the a.c. voltage to give a peak alternating voltage of 1 V (peak to peak of 2 V)
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- Leave this circuit switched on.
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- Switch on the right hand circuit.
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- Adjust the d.c. voltage so that the lamp is the same brightness as the left hand lamp.
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- Measure the deflection of the spot on the oscilloscope. This gives a measure of the
direct voltage across the lamp.
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- Repeat the measurements for a.c. peak voltages of 2 V, 3 V, and 4 V.
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- Plot a graph of direct voltage against peak a.c. voltage
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- Determine the gradient of the graph
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- State the relationship between V d.c. and V peak using the value
obtained from the gradient of the graph
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| Copyright Physics Support Materials 2000 |