PASCO ET-8782 Energy Transfer– Thermoelectric - Manual (Page 6)

Energy Transfer –Thermoelectric Introduction
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2. Input Power
Input Power for the board must be supplied from an external DC power supply capable of 1 amp
at 10 volts. Connect the power supply via the red and black banana jacks on the right-hand side of
the board. Note the polarity: red must be positive. Do not input more than 10 volts.
3. Load Resistors
In Heat Engine Mode, a jumper cable must be connected from the bottom banana jack terminal to
one of the terminals labeled A through D. The load resistance depends on how you connect the
jumper cables. If, for example, the jumper is connected to terminal A, then all of the resistors are
in series in the circuit, and the total load resistance is 20
Ω + 7 Ω + 3 Ω = 30 Ω. If the jumper is
connected to terminal C, the load resistance is 3
Ω. A second jumper can also be used across a
resistor to remove it from the circuit. For example, if the main jumper from the bottom connector
is plugged into terminal A, and a second jumper is connected between B and D, the total load
resistance is 20
Ω; the 7 Ω and 3 Ω resistors are bypassed.
The possible combinations are 3
Ω, 7 Ω, 10 Ω, 20 Ω, 23 Ω, 27 Ω and 30 Ω. If you use a decade
resistance box instead of the on-board resistors, you can supply any value you want. You can also
connect the jumper from the bottom terminal directly to terminal D, which reduces the load
resistance to a few tenths of an ohm (due to the internal resistance of the circuit).
4. Knife Switch
The single pole double throw Knife Switch on the right side of the board is used to select the
mode of operation. In Heat Pump Mode, external power is applied to the peltier device, and heat
is pumped from the aluminum block on the cold side to the block on the hot side. In Heat Engine
Mode, the external power is disconnected, and heat flows back through the peltier, generating
electric current through the load resistor.
5. Voltage and Current
Voltage and current sensors connected to the banana jacks at the top of the board will measure
voltage across and current through the peltier. Note the polarity when you connect the sensors. A
single PASPORT Voltage/Current sensor can be used for both measurements. If you plan to run
the peltier without a current sensor, you must connect a jumper between the current terminals to
complete the circuit.
From the measured voltage and current, DataStudio will calculate the power supplied to the
peltier (in Heat Pump mode) or power generated by the peltier (in Heat Engine mode). DataStudio
will plot a graph of power versus time, which it will use to calculate input or output energy.
6. Temperature Ports
Each aluminum block has a 10 k
Ω thermistor embedded in it. Use the provided Temperature
Cables to connect temperature sensors to the thermistors through the hot-side and cold-side