PASCO ET-8782 Energy Transfer– Thermoelectric - Manual (Page 23)

Model No. ET-8782 Energy Transfer –Thermoelectric
23 ®
Experiment 2:
Teachers’ Notes–Load Resistance and Efficiency
This sample data is in the file “Load Efficiency Data”.
For instructions on using the Smart Tool and Zoom Select in the graph display, click on the
DataStudio Help menu, select Search and look up those terms in the Index.
1) Power generated was greatest for R
L
= 7
Ω.
2) For other values of R
L
, the peltier generated less power because the load resistance did not
match the internal resistance.
3) V
out
= V
NL
when there is no load connected (or when R
L
=
∞).
4) To measure V
NL
, run the cycle with all of the load resistors disconnected, (or leave the knife
switch open for the cooling phase).
5) P
V
NL
2
R
L
R
i
R
L
+
( ) 2
------------------------- =