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Considering the scheme below

schematic

simulate this circuit – Schematic created using CircuitLab

Am, I understand correct, in real life, if I will step-by-step add the parallel resistors, the total curent will grow, and even there only 1V, the value of curent can be over 10 50 100 or more A? And hence, even an 1V voltage source can melt a wire, or create strong magnetic field?

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  • \$\begingroup\$ You forgot to include the Rs of the Voltage source. If ideal then yes, you get 1000A max when R1 reduces to 0.. \$\endgroup\$ – Sunnyskyguy EE75 Jan 12 at 22:37
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Yes, if the various resistances are low enough.

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That is correct until you exceed the ability of the 1 V source to maintain its output voltage.

Batteries have some internal resistance which as you increase the current draw causes the terminal voltage to drop. This is known as the "equivalent series resistance". You can see this yourself if you measure the open-circuit voltage of a battery and then measure again with a significant load.

Mains-powered unregulated power supplies may have a similar voltage droop with increasing current.

Regulated power supplies will have some active circuitry to maintain a constant output voltage up to a specified maximum current. Beyond that the power supply goes into current limit and the voltage reduces to that value which will maintain the maximum current through the load resistance. In your example a 1 V supply with a 1 A current limit will work fine until the 101st resistor is added. Then the voltage will decrease to \$ V = IR = 1 \times \frac {100}{101} = 0.99\ \text V \$ and will decrease further for each additional resistor added in parallel.

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if I will step-by-step add the parallel resistors, the total current will grow?

Yes, by adding resistances will parallel the effective resistance is going to decrease.

the effective resistance of a parallel circuit is always less than the least resistance in that network.

even there only 1V, the value of current can be over 10 50 100 or more A?

Yes, if the power supply is capable enough and the resistors also to be able to dissipate that power.

And hence, even an 1V voltage source can melt a wire?

Yes, current is the one responsible for melting and voltage is the driving force for current.

or create strong magnetic field?

yes it will.

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