Electronic – Some doubts on terminology


I've noticed that sometimes electronic engineers switch terms or have more than one term for the same thing. I wanted to ask, specifically in this question, what are these terms referring to:

  • Resistance looking into the base
  • Resistance from the base
  • Resistance looking into (the) "X"
  • Resistance from (the) "X"
  • Input impedance (or Thévenin equivalent?)
  • Output impedance (also Thévenin equivalent?)
  • If you think there is another term that might be worth clarifying that you know, I'd appreciate it!

Thanks a lot.

Best Answer

Resistance looking into (the) "X"

Apply a test voltage (say 1V) and measure the test current. The resistance looking into the X is the test voltage divided by the current that flowed.

Resistance from (the) "X"

I'm not familiar with this usage.

Input impedance (or Thévenin equivalent?)

Same thing as Resistance looking into (the) "X"

Output impedance (also Thévenin equivalent?)

Same thing as the resistance in a thevenin equivalent.