Why is it important to have resistance in a circuit. Is it possible to not have resistance?

Question

why is it important to have resistance in a circuit. Is it possible to not have resistance in a circuit? Does that mean no resistence infinite power?

Answer 1

A simple circuit could include a source (battery) lead wires and load (light bulb).  Most if not all electrical sources include internal resistance that will limit current.  It is desirable for the lead wires to have minimal resistance to avoid I2R (I squared x R) losses of energy and proper copper wire gages are used to do this (also avoiding too much heat).  The load must exhibit resistance to provide a useful effect (heat light bulb filament to incandescence, etc.).  If resistance is too low (as in a short circuit across the lead wires) the internal resistance of the source will limit current, however maximum current may result with possible damage (lead wires may melt or battery explodes, etc.).  However, infinite power can not result.  A shorted flashlight battery can not lift a cement truck!

Maximum power transfer occurs when impedances (resistances of the source and load) are matched.  However, the desired effect may not require matched impedances.  AC circuits include resistors, reactors and capacitors that are sensitive to frequencies when calculating impedances, while DC circuits employ pure resistances.

Answer 2

Yes! They are called superconductors.

It does not mean infinite power, but it means no losses. So, if you start current in a loop of superconductor, it will keep going round and round with no loss.

Resistance is not required, or desireable, in most circuits. However, superconductors are costly, and have to be kept really cold, so they are rarely used, generally only a few special cases were supermagnets are needed. A few cases, like toasters and incandescent bulbs, do require resistive heat to work. Many circuits also require resistors to work properly. The best situation would be do add semiconductors and conductors that are superconductors at room temp to the materials we already have.

Answer 3

It is not possible to not to have resistance in circuit.Because without resistance the circuit have infinite voltage and infinite ampere. But that is not possible to have a infinite resistance

Answer 4

In an electrical circuit you must have resistance in order to utilize the power (amperage) of the electrons.  With out resistance you have no path of flow.  We have yet to find a resistance free path of flow (material) for electrons.  No resistance mean maximum power potential of available power with out a means of utilizing it.  It is neither infinite or zero, it is nominal, unmeasurable.

Power, needs to have resistance to generate result.  Power (watts) can only provide limited functions.  Power is able to produce heat and magnetism.  Manipulation of these two functions produces many wonderful things.

Answer 5

resistance is the charectristic of the matterial through which the electricity passes.there is no matterial without resistance to electricity.

Answer 6

It is very simple thing, becuase.

Voltage = Current * Resistance. If you will not have any resistance the power would be infinite.

Now the power = voltage * current. Like that it will also become infinite.

Ideally it is not possible to have ZERO resistance.

Answer 7

Resistance in a circuit that is driven by a voltage source controls/determines the amount of current that will flow.  Superconducting wire and superconducting magnets when operated with constant, direct current have zero resistance, zero voltage drop, and dissipate zero power.  Superconductors and superconducting magnets are not uncommon.  They are widely used in the Magnetic Resonant Imaging (MRI) systems located in almost every hospital in the United States.  Since the magnets are held at a constant, low temperature (4 degrees C above absolute zero in most systems), they provide intense, spatialy and temporaly constant magnetic fields that do not suffer any thermally induced variations.