Learn more physics!
How can I know whether one device use AC or DC sources phisically??
- Iyung (age 20)
There is no 'sure fire' way of knowing. There are some clues, however. If you measure the resistance of the input plug with an ohmmeter and find a small value, a few tens of Ohms at most, then it is likely there is an input transformer that requires an AC source.
Of course itís important then to know what voltage and frequency itís designed for. If itís designed for 120 V (or even worse, for 24 V), it would probably be destroyed if you applied 220V. Mike W.
(published on 03/12/07)
Follow-up on this answer.