Generate Voltage / Current to Supply to Thermoeletric Cooler (TEC)

[izzati]

Hello

I generated an analog voltage from NI-SCC-68. The voltage is then measured using a voltmeter and produced exactly the voltage that I wanted. For example, if I generated 5V, the voltmeter reads 5V.

However, when I connect the voltage source from the NI-SCC-68 to a thermoelectric cooler (TEC) (at the same time, I measure the voltage output using voltmeter), the output voltage does'nt show the value that I generated. For example if I generated 5V, the voltmeter reads 0V.

Please help me. Is the problem comes from the thermoeletric cooler (TEC)? Because to operate TEC requires current source. So, do I have to change to current source instead of voltage source?

Thank you.

[johnsold]

TECs are relatively low impedance devices.  A 2 cm x 2 cm device might require several amperes of current.  They can certainly be operated from a voltage source rather than a current source, but whatever source is used it must be able to supply watts of power.  The analog outputs from most DAQ devices can only source a few miiliamperes.  You need some kind of amplifier or electronically adjustable power source for your TEC controller.

Lynn