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# Using Resistor as Dummy Load

#### Ben W.

Mar 2, 2017
3
I apologize if this is a dumb question but here is my dilemma. I've been attempting to use two 10ohm 1W resistors set up in parallel to provide a constant 5 ohm load for a TEG(outputs anywhere from 1-3v). I have my system setup so that I measure voltage across the resistor i.e. - before + after the resistor. I was hoping that with these two values (voltage and resistance) I would be able to calculate how much power the TEG is generating. I did a short test but the numbers didn't quite add up. I'm now also worried that the resistors are providing enough of a load and that I'm just shorting the TEG. I don't know if I should change the resistance or if I'm taking a totally wrong approach to this. Any help or advice would be extremely appreciated. Thank You.

#### davenn

Moderator
Sep 5, 2009
14,197
I apologize if this is a dumb question but here is my dilemma. I've been attempting to use two 10ohm 1W resistors set up in parallel to provide a constant 5 ohm load for a TEG(outputs anywhere from 1-3v). I have my system setup so that I measure voltage across the resistor i.e. - before + after the resistor. I was hoping that with these two values (voltage and resistance) I would be able to calculate how much power the TEG is generating. I did a short test but the numbers didn't quite add up. I'm now also worried that the resistors are providing enough of a load and that I'm just shorting the TEG. I don't know if I should change the resistance or if I'm taking a totally wrong approach to this. Any help or advice would be extremely appreciated. Thank You.

I have no idea what a TEG is ??
Presumably it is expecting a specific load resistance range where it efficiently generate the most output power ?

#### Ben W.

Mar 2, 2017
3
I have no idea what a TEG is ??
Presumably it is expecting a specific load resistance range where it efficiently generate the most output power ?
Much simpler than that. It is a thermoelectric generator, when a temperature difference is applied to either side of it power is created.
https://en.wikipedia.org/wiki/Thermoelectric_generator

#### (*steve*)

##### ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,509
The teg is a bit like a solar panel in that you need to vary the load in order to extract the highest power.

With a fixed resistance load you will get a single data point for each temperature differential. You will not know if the load is allowing you to maximise the power output.

#### davenn

Moderator
Sep 5, 2009
14,197
The teg is a bit like a solar panel in that you need to vary the load in order to extract the highest power.

With a fixed resistance load you will get a single data point for each temperature differential. You will not know if the load is allowing you to maximise the power output.

cheers, Steve

#### CDRIVE

##### Hauling 10' pipe on a Trek Shift3
May 8, 2012
4,960
I'm not exactly sure of what you're looking for. Are you desirous of a circuit that will automatically adjust the load resistance for maximum power dissipated in the load? If you're looking for something simpler you could use a high power wire wound Rheostat. If so you would have to manually plot E x I to find the maximum power point. These things aren't easy to find nowadays.

Chris

#### Ben W.

Mar 2, 2017
3
I'm not exactly sure of what you're looking for. Are you desirous of a circuit that will automatically adjust the load resistance for maximum power dissipated in the load? If you're looking for something simpler you could use a high power wire wound Rheostat. If so you would have to manually plot E x I to find the maximum power point. These things aren't easy to find nowadays.

Chris
Thanks for your advice. I did mange to find a rheostat and following you instructions I got exactly the result I wanted.

#### CDRIVE

##### Hauling 10' pipe on a Trek Shift3
May 8, 2012
4,960
I'm glad to know that.

Chris

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