Analog and electronic circuits

What is the output impedance of an ideal current source?

  1. AZero
  2. BThe same as the load resistance
  3. CInfinite
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Answer: C. Infinite

An ideal current source keeps supplying the same current no matter how the load changes, which means its output impedance is infinite. In contrast, an ideal voltage source has zero output impedance. Real current source circuits are designed to make the output impedance as large as possible.

  • A. Zero output impedance is the ideal voltage source.
  • B. The current must not change with the load, so it is not equal to the load.
  • C. Correct. The current stays constant regardless of the load, so the impedance is infinite.
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