2007-04-26 21:43:34 · 4 answers · asked by yemisi 2 in Science & Mathematics ➔ Physics
All devices obey ohm's law. If temperature increases, so does the resistance and again ohm's law is followed at new resistance. If however, if you cool and keep temperature constant, the same current flows.
Some materials (Zinc Oxide) and some devices (tetrode) show negative resistance characteristics. It is because the reistanc decrease under certain conditions. One can say (in a way) that they do not follow the ohm's law.
In AC the word resistance will be replaced by impedence. It is complex quantity.
2007-04-27 00:09:27 · answer #1 · answered by dipakrashmi 4 · 0⤊ 0⤋
resistors and thermistors. In AC circuits at steady state, coils and capacitors obey a variant of Ohm's Law, V = IZ where Z is a complex quantity.
2007-04-26 21:57:10 · answer #2 · answered by Helmut 7 · 0⤊ 0⤋
all electric devices obeys ohms law. it is a law not a theory.
2007-04-26 21:48:39 · answer #3 · answered by outg426 4 · 0⤊ 0⤋
theoretically, nothing truly obeys ohms law because different temperatures caused by increased current will theoretically increase resistance.
2007-04-26 21:48:44 · answer #4 · answered by Anonymous · 0⤊ 2⤋