Op-amp circuits worksheet with answers

Free printable Op-amp circuits worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
−+Vout​Rf​ = 22 kΩVin​ = −1.2 VR1​ = 4.7 kΩI1​

The op-amp is ideal and runs from ±15 V supplies. Find the current I1 through R₁, flowing towards the op-amp.

Vin = −1.2 VR1 = 4.7 kΩRf = 22 kΩ
I1 = mA
2.Easy
−+Vout​Rf​ = 10 kΩVin​R1​ = ?

An inverting amplifier with an ideal op-amp must have a voltage gain of −5. The feedback resistor is Rf = 10 kΩ. Find the input resistor R1.

Av = −5Rf = 10 kΩ
R1 = kΩ
3.Medium
−+Vout​R2​ = 100 kΩV1​ = 1.5 VR1​ = 4.7 kΩV2​ = 1.9 VR3​ = 4.7 kΩR4​ = 100 kΩ

The difference amplifier uses an ideal op-amp with ±15 V supplies, with R3 = R1 and R4 = R2. Find the voltage V− at the inverting input.

V1 = 1.5 VV2 = 1.9 VR1 = R3 = 4.7 kΩR2 = R4 = 100 kΩ
V− = V
4.Medium
−+Vout​R2​ = 100 kΩV1​ = 1.4 VR1​ = 47 kΩV2​ = 0.2 VR3​ = 47 kΩR4​ = 100 kΩ

The difference amplifier uses an ideal op-amp with ±15 V supplies, with R3 = R1 and R4 = R2. Find the output voltage Vout.

V1 = 1.4 VV2 = 0.2 VR1 = R3 = 47 kΩR2 = R4 = 100 kΩ
Vout = V
5.Hard
−+Vout​C = 0.1 µFVin​ = −2.1 VR = 4.7 kΩ

The integrator uses an ideal op-amp with ±15 V supplies; its output saturates at ±14 V. The capacitor is uncharged when a constant input Vin = −2.1 V is applied at t = 0. How long after t = 0 does the output reach saturation? Find t.

Vin = −2.1 VR = 4.7 kΩC = 0.1 µFVsat = ±14 V
t = ms
6.Hard
Vin​V1​Vout​stage 1: invertingR1​ = 22 kΩRf1​ = 22 kΩstage 2: non-invertingR2​ = 47 kΩRf2​ = 1 kΩ

Two ideal op-amp stages are connected in cascade: an inverting amplifier (R1, Rf1) followed by a non-inverting amplifier (R2 to ground, Rf2 in the feedback). Both run from ±15 V supplies. The input is Vin = 0.8 V. Find the output voltage Vout.

R1 = 22 kΩRf1 = 22 kΩR2 = 47 kΩRf2 = 1 kΩVin = 0.8 V
Vout = V

Answer key

  1. 1. I1 = −0.2553 mA
  2. 2. R1 = 2 kΩ
  3. 3. V− = 1.815 V
  4. 4. Vout = −2.553 V
  5. 5. t = 3.133 ms
  6. 6. Vout = −0.817 V

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