design of linear regulator efficiency tester under differnent load conditions

[yogece]

hi,
  I would like to design a liner regulator efficiency tester such as 78xx, LDO.can any one suggest me from where to start

[digsys]

This has to be the easies assignment ever !
Open up EXCEL - create at least 7 columns - Vin, Iin, Pin, Vout, Iout, Pout, Efficiency
Eff = Pout/Pin x100
That's 100% accurate for Resistive loads, for ANY type of Linear Regulator (or use RMS for changing loads).

[yogece]

No.I thought of designing automated efficiency tester using arduino;I need some suggestions regarding the circuit designing.


Thanks for your reply

[Bored@Work]

What digsys tries to tell you is that building a linear regulator efficiency tester is a pointless activity. The efficiency can be calculated with good accuracy and need not be tested.

can any one suggest me from where to start

By getting your theory right.

[jmaja]

This has to be the easies assignment ever !
Open up EXCEL - create at least 7 columns - Vin, Iin, Pin, Vout, Iout, Pout, Efficiency
Eff = Pout/Pin x100
That's 100% accurate for Resistive loads, for ANY type of Linear Regulator (or use RMS for changing loads).

That's true for switching regulators as well, but how do you know Iin as a function of Iout? For larger loads you can assume Iin=Iout for linear regulators, but not for low loads, since they have ground pin currents from few uA to few mA.

[digsys]

That's true for switching regulators as well, but how do you know Iin as a function of Iout? For larger loads you can assume Iin=Iout for linear regulators, but not for low loads, since they have ground pin currents from few uA to few mA. 

It's still a loss DUE to the regulator, therefore included in the efficiency.

[yogece]

What digsys tries to tell you is that building a linear regulator efficiency tester is a pointless activity. The efficiency can be calculated with good accuracy and need not be tested.

can any one suggest me from where to start

By getting your theory right.

I would like to design something like this

[jmaja]

It's still a loss DUE to the regulator, therefore included in the efficiency.

Of course, but it makes some sense in measuring the efficiency at different loads instead of just calculating it, which you can do very accurately at higher loads.

[Jon86]

Inrush currents and ripple with an arduino? Good luck...