# Ohm's Law in Practise [closed]

When the AUX pin of a stereo is connected to my mobile phone's audio female port, I just measured the voltage at the end of this AUX pin (No load is connected) approximately 2mV using a DMM. But when I measured the current, it didn't indicated any current in the DMM. According to Ohm's law, voltage is current times the resistance. When relating this basic law to my practical case, it doesn't matching. How can it be realized?

## closed as off-topic by The Photon, John Rennie, Qmechanic♦Sep 20 '18 at 7:51

• This question does not appear to be about physics within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

• You need to make this more clear to be able to get a useful answer. The AUX pin of what? Of the phone? Of a stereo? How did you measure the current? If you didn't read "a uA current" what did you read (no current or a larger than uA current)? – The Photon Sep 20 '18 at 2:06
• Also, this is probably a better question for Electrical Engineering rather than Physics (but not until there is enough information provided to make the question answerable). – The Photon Sep 20 '18 at 2:07
• was the aux line actually connected to the phone? if the circuit was open, then no current would flow. also when you made the measurement, was there an audio signal flowing between the devices? no signal means no current and no voltage. Finally, were you using the AC or DC range on the meter to take your measurements? By the way, the nominal impedance of the AUX port is 10,000 ohms. – niels nielsen Sep 20 '18 at 3:00
• FYI, the question has now been cross-posted to EE. – The Photon Sep 20 '18 at 3:01