EL22 · Sem 4 · Linear ICs

Op-amp differentiator

Aim: Convert a triangle wave into a square wave by differentiation.

🧪 Live simulation🧊 Real-time 3D bench⚠ Simulated values, not physical measurements

🔬 Virtual lab

Starting the lab…

📘 Theory

A capacitor at the input and a resistor in feedback give Vout = −RC·dVin/dt. A small series resistor limits the high-frequency gain so the circuit does not amplify noise.

Vout = −R·C·dVin/dt

🧰 Apparatus (virtual)

Op-amp
100 nF input
10 kΩ feedback
100 Ω series
triangle-like input

📝 Procedure

Run and see the output steps where the input slope changes sign
Measure the output level and compare with RC × slope
Add noise thought: why is a pure differentiator noisy?
Change R and observe

Observations and result (kept on this device)

🎤 Viva questions

Why are differentiators rare in practice

They amplify high-frequency noise.

What does a sine wave become

A cosine (shifted by 90°), with amplitude proportional to frequency.

🛡️ Safety

Virtual lab at safe low voltages. On a real bench: switch off before rewiring, check capacitor polarity, and never touch mains wiring without supervision.