3B SCIENTIFIC PHYSICS U8482360 Instrucciones De Uso página 7

6.2 Measuring the current/voltage characteristic
(I /U curve) of a diode
A A
Figure 5 shows the different regions of a typical
curve, which can be measured using two circuits.
The cutoff region (Sp) and the current onset region
(A) are measured by applying a negative anode
voltage, which is progressively reduced up to the
beginning of the space-charge region (R). This part
of the measurement ends with U
•
For the latter regions, connect the circuit as
shown in Figures 3a/b.
•
Determine how the anode current I
on the anode voltage U
anode voltage step by step from -8 V to 0 V.
•
Plot the values of I
A
Fig. 3a Circuit set-up for measuring the current onset
region
Fig. 3b Circuit connection of the 500 V DC power
supply (U33000)
The space-charge region (R) and the saturation
region (S) of the curve are measured by applying a
positive anode voltage that is varied over the range
0...250 V.
•
Connect the circuit as shown in Figures 4a/b.
•
Determine how the anode current I
on the anode voltage U
voltage step by step from 0 V to 250 V.
•
Plot the values of I
A
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= 0 V.
A
depends
A
by decreasing the
A
and U on a graph.
A
depends
A
by raising the anode
A
and U on a graph.
A
Technical amendments are possible
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Fig. 4a Circuit set-up for measuring the space-charge
and saturation regions
Fig. 4b Circuit connection of the 500 V DC power
supply (U33000))
Fig. 5 Current/voltage characteristic of a diode