- Build an inverting op-amp with a TL072: kΩ, kΩ. Gain is . Drive with a 1 kHz, 100 mVpp signal generator. Watch the output: should be a 1 Vpp signal, inverted. Sweep the input frequency up; watch the gain start dropping above the GBW limit (around 300 kHz with a 3 MHz GBW op-amp at gain 10).
- Add a 100 nF capacitor in parallel with : turns the inverting amp into a low-pass filter with cutoff Hz. Sweep frequency and watch the magnitude roll off above the cutoff at 20 dB/decade.
- Build an instrumentation amp with three TL072s and the topology in Section 3.7. Apply a small differential signal across two long wires while touching them lightly to a 50 Hz common-mode source (hover near a power cord). The in-amp recovers the small differential signal cleanly while rejecting the mains.
- Build a Sallen-Key low-pass filter for kHz with a TL072. Use the design from Section 5.3 and the SPICE netlist there. Drive with a function generator from 100 Hz to 100 kHz; record amplitude at each frequency; plot magnitude vs frequency. Verify the cutoff is near 1 kHz and the rolloff is 40 dB/decade.
- Wire up a 555 in astable mode for 1 kHz. kΩ, kΩ, nF: kHz. Watch the square wave on a scope.
- Build a peak detector with a precision rectifier (one op-amp, one diode, one cap, one bleeder resistor). Drive with a slowly rising sine; watch the output stick at the peak.
- Code a SAR ADC simulation in Python: generate a noisy sine wave, sample at , simulate the SAR's binary search to produce 12-bit codes, and plot the FFT of the samples to see the SNR. Add a hypothetical 1 ns clock jitter and watch the noise floor rise; verify the ENOB drops by the predicted amount.
- Design a Butterworth low-pass with scipy at Hz, fourth-order. Plot the s-plane pole locations. Verify they sit on a circle of radius in the left half-plane.
- Build a Wien bridge oscillator with a TL072 and a small incandescent bulb (12 V, 25 mA) in the gain divider for AGC. Choose kΩ, nF for kHz. Watch the sine on the scope: it should start small from noise and grow to a stable amplitude limited by the bulb's resistance change.
- Capture a power trace with a low-cost oscilloscope. Solder a 1 Ω shunt in series with an Arduino's , scope across the shunt, run the AES library, and capture. Even at the few-MS/s of a USB scope you can see structure that correlates with crypto rounds. This is the threshold of side-channel attack.
section 12 of 133 min read