I've got a (hopefully) quick question.
For my project I want to add a voltage regulator, I've bought the step-up/step-down voltage regulator from pololu Pololu 6V Step-Up/Step-Down Voltage Regulator S18V20F6. I want to add it in an already soldered circuit (PCB so can't make too many changes). I'f I let's say put in between my batteries and the off/on switch, will it draw any energy from my batteries if the switch is off?
So what I'm actually asking is if someone knows the circuit is closed if I attach the voltage regulator to my batteries (plus and minus) and not attach any output from the voltage regulator?
To avoid any "regulator quiescent current" worries, simply leave the regulator attached and switch the unregulated input power.
Note it's probably unlikely, but it's POSSIBLE that the regulator puts out more voltage than spec in the milliseconds it takes to power up.
Therefore, I suggest placing a resistor across the output of the regulator without the Arduino connected (to simulate the load of the Arduino), place an oscilloscope on the output and toggle the input power. Look for any momentary voltage spikes that pop up, then settle down to the normal voltage.
If you see spikes, then do NOT connect the regulator and Arduino as I suggested above.
This is very unlikely, but better safe than sorry.