3.10.2
2-Terminal Measurement, Current Mode
This measurement is similar to the 2-terminal voltage mode, with the difference that the current is controlled and
the voltage measured. The maximum range of current is +/-1 amp and the resultant v/-40V.
Notice that the device connections are different for voltage and current mode.
A warning dialog pops up
when switching between them.
Figure 12 shows the previously described diode array measured in current mode.
(a) Control Settings
(b) Result
Figure 12: 2-Terminal Measurement, Current Mode
3.11
Small Signal Transistors
In the following images we show the control settings and curves for three small-signal devices: 2N4401 NPN BJT
(figure 13, page 15), , 2N4403 PNP BJT (figure 14, page 16) and 2N7000 N-Channel MOSFET (figure 15, page
17). All these devices are packaged in a TO-92 package and are very limited in dissipation.
These settings and results will be useful in providing a starting point for setting the controls for other small-
signal devices.
3.12
Solar Cells
The 2-terminal VI curve control panel for measuring solar cells is shown in figure 16(a) on page 18. The solar cell
is connected with its positive terminal to the collector (red) terminal of the curve tracer. The solar cell negative
terminal is connected to the emitter (black) terminal of the curve tracer.
A typical curve is shown in figure 16(b) on page 18.
At zero terminal voltage the cell is delivering
I
sc
, the short-circuit current, about 2.9 milliamps. At zero output
current, the cell is delivering
E
oc
, it’s open circuit voltage, around 5.9 volts. The intersection of the curve with the
vertical (current) axis is
I
sc
, the short-circuit current. This varies with light level. The intersection of the curve
with the horizontal (voltage) axis is
E
oc
, the open-circuit voltage.
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