find current and voltage?

1.

The MAGNITUDE of the current through the wire connecting Points A and B____mA

2.

The voltage at Point A________V

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  • 1 month ago
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    Resistances are in kΩ, currents in mA. Let the top of the circuit be node V. Apply KCL at V. Currents leaving V are positive:

    +7.9 + V/8.2 + V/12 - 18.3 = 0

    V(1/8.2+1/12) = 18.3 - 7.9 = 10.4mA

    V = 10.4/(1/8.2+1/12) = 50.66V

    The current down R2 = 50.66/12 = 4.22mA

    The current from B to A = 18.3-4.22 = 14.08mA or about 14mA with 2 significant digits. 

    14mA from B to A <<< 1.

    Va = 51 Volts <<< 2.

    Check by comparing power delivered to power consumed:

    18.3e-3*50.66 - 7.9e-3*50.66 = 0.5269W

    Consumed by resistance

    50.66²/8.2k + 50.66²/12k = 0.5269W checks

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