SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/hame-opamp-gain-38

An inverting op-amp circuit has a 1,800-ohm input resistor and a 68-kilohm feedback resistor. What is its absolute voltage gain?

About 38, feedback resistor divided by input resistor.

Start playing free

  1. About 76
  2. About 38 ✔
  3. About 0.03

Why: Inverting gain is the feedback resistance divided by the input resistance. 68,000 divided by 1,800 is about 37.8, so 38.

Huh, didn't know that: A typical op-amp has very low output impedance (E7G01).

The dad joke
Why does the amplifier refuse to work? It demands proper compensation.
Like this card?
Play the game

References

Answer: About 38. Inverting gain is the feedback resistance divided by the input resistance. 68,000 divided by 1,800 is about 37.8, so 38.

  1. NCVEC 2024-2028 Amateur Extra Question Pool, E7G10 (4th errata, Feb. 4, 2026) www.ncvec.org/downloads/2024-2028%20Extra%20Class%20Question%20Pool%20and%20Syllabus%20Public%20Release%20with%204th%20Errata%20Feb%204%202026.pdf
    C. 38
    Checked 2026-10-11.
  2. NCVEC 2024-2028 Amateur Extra Question Pool, E7G01 (4th errata, Feb. 4, 2026) www.ncvec.org/downloads/2024-2028%20Extra%20Class%20Question%20Pool%20and%20Syllabus%20Public%20Release%20with%204th%20Errata%20Feb%204%202026.pdf
    A. Very low
    Checked 2026-10-11.

Think this answer is wrong? Tap "Challenge this answer" on the card in the game and tell us why.

Test yourself in the game

Ham RadioHow is battery operating time calculated?Ham RadioHow do you calculate the power dissipated by a series linear voltage regulator?Ham RadioAn FM signal deviates 3,000 Hz each side of the carrier with a highest modulating frequency of 1,000 Hz. What is the modulation index?

That's stuff everyone should know.