Question

what is the derivative of 1/Req(equivalent resistance) and how

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Answer 1

Answer:

Step-by-step explanation:

Let the resistances be R1 &R2

For series resistance:

In series condition same current flows through the entire circuit.Thus same current I amp will flow through two resistors.But what varies is voltage drop.It varies according to resistance values.

Let drop on R1 be V1 & drop on R2 be V2.

Total voltage V=V1+V2

We know that V=I*Req(ohms law)

So I*Req=(I*R1)+(I*R2)

Req=R1+R2

For parallel resistance:

In parallel circuits voltage drop across resistors will be same but the current flowing through each resistor depends on resistance valule.

Let current through R1 be I1 & current through R2 be I2.

I=V/Req(ohms law)

So I=I1+I2

V/Req=(V/R1)+(V/R2)

1/Req=(1/R1)+(1/R2)

Req=(R1*R2)/(R1+R2)