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power Output of low power application

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sarmad_101

sarmad_101

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Hi All,

I want to ask a question. I am confused about it.

I made a low power application circuit that work with thermocouple with rectifier at the beginning then the booster and then the voltage stabilizer IC to make the output constant at 2.7. The 2.7V drive micro-controller.

Now at 2.7 Volt I have to check the power of the circuit.

As the input is too small means at 0.8 V i got 2.7 V at the output and the current is in 0.1 mA.

If I connect the resistor at the output the output which is 2.7 V become zero and then micro-controller do not run.

I also try to measure current with multimeter at the output but multimeter have its own resistance so that doesn't work out.


How should I check the power at the output ?

Is there any way....???


Thank you in advance.
 

Connect a 0.1R resistor between the output of the regulator and rest of the circuit. Measure voltage across the 0.1R resistor. Current = (V/0.1). Power = V (measured) * I (calculated)

Hope this helps.
Tahmid.
 

Sorry but I didnot get your point.

' between the output of the regulator and rest of the circuit'.

and one more thing IF I connect the 0.1R resistor then the power dissipation would be too high or ???
 

Your 2.7V goes to power the rest of the circuit, right?

Remove the connection from 2.7V to rest of the circuit.
And place a 0.1R resistor there.

So, the 2.7V powers the circuit through the 0.1R resistor.

Power dissipation depends on current flowing through.
Since you say it's a low power application, dissipation shouldn't be too high. Although, you should define what you mean by "low power" to have a better idea.
 

ok I got it..
ya 2.7 V goes to all the circuit.. to power up every thing on board.

Low power means it is working on 0.7 volts with thermocouples.
Booster step up the voltage to 3 V and the regulator to stable the voltage at 2.7 V.

thats all...!!!
 

So, current flowing through should be very small. Power dissipation will, thus, not be too high. You might get too low a voltage reading, in which case, you might want to increase the resistance of the resistance. Experiment with values between 0.1R and 1R.

Hope this helps.
Tahmid.
 
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