# I want to convert 3mv output to 5 Volts

Discussion in 'The Projects Forum' started by Sankalpsood, Jan 19, 2016.

1. ### Sankalpsood Thread Starter New Member

Jan 19, 2016
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I am making a project to use seabeck effect to run a 5 volt motor to run a fan.
But the problem is that , the output voltage by Seebeck effect is around 3 millivolts. So I basically need a circuit or a device to amplify that to 5 volts.

2. ### Sankalpsood Thread Starter New Member

Jan 19, 2016
9
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That is 5 volts not brother.. #sorry

Apr 5, 2008
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4. ### Sankalpsood Thread Starter New Member

Jan 19, 2016
9
0
not any op amp circuitry can work?

5. ### crutschow Expert

Mar 14, 2008
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It can certainly amplify the voltage but the op amp power must be supplied by external power supplies

6. ### profbuxton Member

Feb 21, 2014
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Just use a thermocouple amplifier. Standard product available from instrument companies. Will output 4 to 20 ma or 1 to 5 volts(or other)

7. ### Papabravo Expert

Feb 24, 2006
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1,850
Amplifiers cannot make something out of nothing. The power, in watts, produced by ANY circuit is always less than the power in. Sometimes it is much less. Just to throw out some numbers let us assume that your device can produce 3 mV @ 100μA. The power input is 300 nW. Let us say we achieve the incredible efficiency of 80%, the power out will be 240 nA. This power level at 5V will result in an output current of 48 nA. I can tell you that that amount of current will NOT be able to turn a fan.

This idea is not dissimilar to the idea of harvesting "free RF energy" from our surroundings. They are both tasks of monumental futility.

8. ### Picbuster Member

Dec 2, 2013
391
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look at the TL site or microchip use 3 x mcp6n11 3mV in last stage 5V out but you have to use a noise free pwr supply.

9. ### Kermit2 AAC Fanatic!

Feb 5, 2010
3,854
968
POWER is a product. It can be estimated by multiplying a voltage and a current.
The product is called watts or volt-amperes.
IT CANNOT BE INCREASED by amplification.
Volts can be increased but current will decrease.
Current can be increased but volts will decrease.
Always, if you multiply, the two you will get the same answer.
POWER cannot be increased by an electronic circuit of any kind.
To increase power, more power must be added.
Consider your stereo. The audio signal you put in the back panel is not capable of moving a speaker cone. The signal coming out is much more powerful.
Look at the wall socket where the amp is plugged in and tell us where this increased audio power comes from.

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10. ### Papabravo Expert

Feb 24, 2006
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Think of an amplifier as an electronic copy machine. It makes a copy of a low level signal by using the power from the wall socket. As always the power out will be less than the power in.

11. ### ErnieM AAC Fanatic!

Apr 24, 2011
7,443
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If you place 1,667 thermoelectric devices in series you will obtain your desired voltage without amplification.

Good luck getting any appreciable current out of it.

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12. ### tcmtech Well-Known Member

Nov 4, 2013
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Well if they are configured as a common 12 volt 50 watt or larger Peltier unit 5 volts at a few hundred milliamps or more would no be hard at all.