Today we’re going to look at temperature
and how it affects the IV curve. We’re also going to look at how to measure and record
the temperature. In a previous demo we looked at light and how light affected the IV curve.
As we lowered the illumination, we saw that there was less current produced in the solar panel, causing
a dramatic effect to the first half of the IV curve. In today’s demo, we’re going to change
the temperature, and as we change the temperature, we’ll see a change in voltage on the IV curve.
As we increase the temperature, we expect to see a decrease in voltage, and we’ll see a
dramatic change to the second half of the IV curve. We’ll be using the new N6784A General
Purpose SMU module to capture the IV curve. Let’s heat up the solar panel and capture another
IV curve. As you can see, the voltage decreases as the temperature increases. We can repeat
this process. Since temperature affects the IV curve, we have included it in our demo program. To measure the temperature, we have attached
a 10K thermistor to the panel. We will use the 34972A LXI Data Acquisition Switch Unit
to record the temperature. The 34972A can easily be expanded to measure multiple points
of temperature, voltage, current, or resistance up to sixty 2-wire measurements per mainframe. Another nice feature is the 34972A can be
controlled and monitored via the front panel, USB, or LAN. We can add WiFi using a pocket
access point. The pocket access point is connected to both a LAN connector and it gets
its power from the USB port. The 34972A provides a web page, which we can
now access wirelessly using a standard browser. In addition, we can create an app for an iPhone
or iPod Touch to monitor the temperature remotely. We have seen the effects that temperature has on
the IV curve, and the interfaces on the 34972A make it easy to make these measurements, even remotely.