The function of several connected resistors can be replaced by a resistor, which is the equivalent resistance of those resistors. That is to say, no matter how many resistors there are in any circuit, one resistor can be used instead. Without affecting the voltage at both ends of the original circuit and the change of current intensity in the circuit.

This equivalent resistance is calculated by the equivalent series-parallel formula of multiple resistors. In other words, this equivalent resistance will not have any influence on the voltage and current of the whole circuit after replacing the original resistance, so this resistance is called equivalent resistance in the loop.

Extended data

The equivalent resistance of a series circuit is equal to the sum of the series resistances. If two resistors are connected in series, R=R 1+R2. The resistance value of series circuit is the sum of the resistance values of series resistors, and the method of series resistor is often used to share the excess voltage in the circuit.

The reciprocal of the equivalent resistance of parallel circuit is equal to the sum of the reciprocal of each branch resistance. If two resistors are connected in parallel, there is1/r =1/r1+1/r. The more parallel resistors, the smaller the equivalent resistance, that is, the smaller the resistance. In parallel circuit, the distribution of current is inversely proportional to resistance.

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