Similar Posts

Subscribe
Notify of
13 Answers
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
indiachinacook
1 year ago

In practice, there is almost always a resistance, in case of doubt from the cables or the voltage source; Then you have to count these resistors together and use them in R. If the resulting resistance is very small, then the current becomes very large, as Ddir Formula predicts. In practice, this is complicated by the fact that the resistor is suspended from the temperature and the apparatus is strongly heated by the high current flow at low resistance; In addition, the high current at the source of the chip can lead to any effects which must be taken into account.

Real R=0 can only occur under exotic conditions (supra conduction), and then the formula is of course worthless.

ano78577
1 year ago

No, you can’t. If there is no resistance you have a short circuit.

You always have resistance, for example in the cables or in a battery.

heilaw
1 year ago
Reply to  ano78577

A short circuit also has a resistance.

Kelec
1 year ago

In principle, this formula applies only to ohmic resistors and then only in the static state.

Even if R=0 is theoretically assumed for any circuit, the current flow in this circuit increases continuously and is then of course arbitrarily large. The magnitude of it after the time t is then determined by the inductance and the voltage.

Practically, however, you always have effects that limit the current, but also for those that do not necessarily have to apply the Ohmic Law, but some of the influencing factors such as cable resistances are of course pure Ohmsch and others can be linearized around the working point and then considered as quasi Ohmsch.

Spikeman197
1 year ago

well, if you have other information….e.g. the power, length/thickness/material of the wire, charge quantity and service life, …

It doesn’t work out by the voltage!

Traveller5712
4 months ago

Yeah, that’s when you know the tension.

Since there are no artificial resistances, there are only natural resistances (contact points, surface resistance material etc). However, this is so small that the resistance can be set to 1.

Speak: In this case, the current in ampere is as large as the voltage.

U = 24V -> I = 24 A

heilaw
1 year ago

Clear with the Ohmic Law R = U/I.

Then you have the resistance value.

CatsEyes
1 year ago

So: https://www.electronicdeveloper.de/AllPURI2.aspx

Update:

Of course, R=0 goes in the direction of infinity with the current, which is then only limited by line and voltage source internal resistances.

hologence
1 year ago

there are always resistors, at least the internal resistance of the voltage source.

ScottyE
1 year ago

This also explains the division by zero

germanils
1 year ago

If you don’t know the resistance, you can’t use it in the formula, so no.

Fragenwuerfel
1 year ago

Not realistic.

nematode
1 year ago

I’m sure your question has a background. A task, maybe? So the question is completely pointless.