Why does the DMM make this circuit "work" ? (Power issues : servo & bluetooth)

Chetan_:
I just want to know which 3.3V regulator you used I am also with the same project.

i'm still prototyping and haven't even settled on how to supply the power properly - at the moment i'm using the LD1117A(3v3) - it's a LDO type. (although also using a DC-DC step-down converter - based on LM2596 chip)

Grumpy_Mike:
No.
You put the filter between the break out board and the servo.

so you mean like this ?

meanwhile, on your webpage that you linked, it says using inductance values of tens of milli-henries.

i've been calculating what length and radius of coil that would involve and it's huge !

is my current circuit really needing that high a value - i can't imagine that's what my DMM was "contributing" ?

what sort of inductance/choke levels would be reasonable for 6V spikes of 100mA ?
(is there a formula for this and what would the 'phenomena' be called ?)