What is the internal resistance of a current source with an EMF of 12 V if, when a resistor with an unknown resistance is connected to it, a

Question

What is the internal resistance of a current source with an EMF of 12 V if, when a resistor with an unknown resistance is connected to it, a current of 2 A flows through the circuit? A voltmeter connected to the source terminals shows 8 V.

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Sigridomena 3 years 2021-07-17T14:04:39+00:00 1 Answers 7 views 0

Answers ( )

  1. Bo
    0
    2021-07-17T14:06:28+00:00
    Reply

    Explanation:
    Second question:
    U
    =
    I
    2
    ×
    R
    2
    =
    4
    A
    ×
    9
    Ω
    =
    36
    V
    First question:
    You could use
    1
    R
    =
    1
    R
    1
    +
    1
    R
    2
    +
    1
    R
    3
    =
    1
    18
    +
    1
    9
    +
    1
    6
    =
    1
    3
    →
    R
    =
    3
    Ω
    Or:
    You can calculate the currents through the other resistors, add them all up and recalculate the total resistance (voltage already calculated):
    I
    1
    =
    U
    R
    1
    =
    36
    V
    18
    Ω
    =
    2
    A
    I
    2
    =
    4
    A
    (as given)
    I
    3
    =
    U
    R
    3
    =
    36
    V
    6
    Ω
    =
    6
    A
    Now
    R
    =
    U
    I
    =
    36
    V
    2
    A
    +
    4
    A
    +
    6
    A
    =
    36
    V
    12
    A
    =
    3
    Ω

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )