Mangesh4438
Member • Sep 23, 2011
Ohm law
Ohm says i=v/r but at some condition current increases then voltage decreases how is that?
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Replies
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Member • Sep 23, 2011
There are some electrical circuits which do not obey Ohm's law. For example, the p-n junction diode. In the p-n junction diode, current does not increase linearly with applied voltage. This happens because the value of "resistance" is not constant as a function of applied voltage. Further, the current only increases significantly if the applied voltage is positive, not negative.Are you sure? This action cannot be undone. -
Member • Sep 23, 2011
check out the limitations of ohm's law....Mangesh4438Ohm says i=v/r but at some condition current increases then voltage decreases how is that?Are you sure? This action cannot be undone. -
Member • Sep 23, 2011
may be the resistance decreases.. 😛 active devices such as transistors, diodes etc will not obey ohm's lawAre you sure? This action cannot be undone. -
Member • Sep 23, 2011
Source resistance. When load resistance decreases, current increases, and voltage drop at source side appears. For example:V battery= 14,4VR lamp = 4 OhmR starter = 0.144 OhmR internal of a battery= 0.024 OhmI1=Vbat/(Rlamp+Rbat)=3,57A Vlamp=Vbat-I1*Rbat=14.28VI2= Vbat/(Rstarter+Rbat)=85,7AVstarter= Vbat-I2*Rbat=12,34VMangesh4438Ohm says i=v/r but at some condition current increases then voltage decreases how is that?Are you sure? This action cannot be undone. -
Member • Sep 24, 2011
have you not ever come across varistors or non-linear resistors or lightening arrestors.
we can have material to follow ohm law only in the range we want by design and then can vary itsbehaviour with voltage.Are you sure? This action cannot be undone. -
Member • Sep 25, 2011
If you are talking about real circuits the culprit may be the impedance of the source. The out put voltage of some power supplies could be higher when the load has a high resistance than when it has a low resistance. Ohm's law is still obeyed if one considers the total resistance, that is, source resistance plus load resistance.Mangesh4438Ohm says i=v/r but at some condition current increases then voltage decreases how is that?
P.S. Sorry, did not notice that Oleg had covered this already.Are you sure? This action cannot be undone. -
Member • Sep 29, 2011
Ohm's law is created for conductor : The current flow to a conductor at a constant temperature and for a fixed material is proportional to the voltage applied across the conductor. Didode is not that conductor ohm mentioned.Are you sure? This action cannot be undone.