Question about a simple test circuit

Eh?? "GND function generator"?? Wazzat?? If you remove the ground line of a circuit, without knowing the other connections and circuit topology and components, the actions / results will be non-determinable - from nothing to ZAP!

Hi, i've realized (with breadboard) a simple circuit: a pic that drives a led in a way decided by input pins value. My problem is not circuit itself, but how i've connected it: i've used a regulated DC power supply (with 24V as output (this value is settled on circuit to 3.3V with a linear regulator)) and a function generator. GND power supply is connected to GND function generator. Sometimes (in randomic way) i see power supply current higher than normal. After some test i've seen that current returns to its normal value if i disconnect function generator gnd (if i disconnect function generator signal probe, nothing changes). Power supply and function generator are connected to the same electrical outlet. Why i have this effect?How can resolve it? Thanks

First off, converting 24 Volts to 3.3 with a linear regulator will overheat the regulator with a small current draw. Drop down to a lower voltage on your power supply. Question, is there a ground connection to the negative of the power supply, if so remove it, it's usually just a metal tab that goes between ground and negative. This could be causing a problem with your signal generator. If you can't do that, use an isolation transformer on the power supply or the signal generator, but not both.

Shaun