PASCO TD-8550A THERMOELECTRIC CONVERTER - Manual

Instruction Sheet
for the PASCO
Model TD-8550A
THERMOELECTRIC CONVERTER
012-04929A
5/92
Introduction
The PASCO scientific Thermoelectric Converter
consists of a thermoelectric heat pump sandwiched
between two aluminum metal legs. Electric current
from the thermoelectric heat pump can drive a small
motor that has a fan attached to its shaft. The Con-
verter can demonstrate the Seebeck effect (discovered
in 1821). In this effect, a temperature difference
across the thermoelectric heat pump gives rise to a
current that drives the small motor (
∆
T
→
E). For
example, when one leg is in hot water and the other is
in cold water, the small motor turns the fan. The
Converter can also demonstrate the Peltier effect
(discovered in 1834). When a current is passed
through the thermoelectric heat pump, a temperature
difference results (E
→ ∆
T). One of the legs becomes
warm while the other leg becomes cooler. Finally, the
Converter acts as a “thermal capacitor”. After a
current is passed through the Converter to create the
temperature difference (E
→ ∆
T), flip the switch (
∆
T
→
E), and the temperature difference causes a current
that drives the small motor.
Figure 1 shows the top portion of the Thermoelectric
Converter. Put the switch in the “up” position (toward
∆ T ➡ E
E ➡ ∆ T
+
–
TD-8550A
Thermoelectric
Converter
scientific
A) Place one leg in icewater, one in hot
water. Fan rotates due to
∆ T.
With both legs in same temp water,
fan won't rotate.
B) Connect 5 V, 3 A DC
supply to terminals.
One leg warms,
one cools.
5V 3A
2min
MAX
A)
B)
DO NOT EXCEED 2 MIN OR 8 V!
∆ T ➡ E
E ➡ ∆ T
+
–
TD-8550A
Thermoelectric
Converter
scientific
A) Place one leg in icewater, one in hot
water. Fan rotates due to
∆ T.
With both legs in same temp water,
fan won't rotate.
B) Connect 5 V, 3 A DC
supply to terminals.
One leg warms,
one cools.
5V 3A
2min
MAX
A)
B)
DO NOT EXCEED 2 MIN OR 8 V!
Figure 1 Switch Position
∆
T
→
E) in order to demonstrate the Seebeck effect
(temperature difference causes electric current).
Connect a source of electric current to the red and
black banana jacks and put the switch in the “down”
position (toward
E
→ ∆
T) to demonstrate the Peltier effect (current
through the thermoelectric heat pump causes a tem-
perature difference).
➧
NOTE: The recommended voltage and current
is 5 Volts and 3 Amps (DC). Do not exceed 8
Volts. Do not run the 5 Volt, 3 Amp current
through the device for more than 2 minutes.
Equipment Needed:
• Cups for hot and cold water
• DC Power supply capable of 5 Volts and 3 Amps
• Patch cords
Recommended Equipment:
• TD-8556 Steam Generator
• SF-9584 AC/DC Low Voltage Power Supply or
SF-9582 12 Volt AC/DC Power Supply
• SE-9750 and SE-9751 Banana Plug Patch Cords
Optional Equipment:
• Digital thermometer (such as PASCO Model SB-
9631 or Model SE-9086)
Theory
A transformation whose only final result is to trans-
form into work heat extracted from a source which is
at the same temperature throughout is impossible.
Lord Kelvin