Real-World Circuit Design
Like Duolingo, but for Real-World Circuit Design. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
For the part of you with thirty open tabs that never became anything.
26 levels across 4 sections, about 52 minutes end to end, roughly 10 days at five minutes a day. It moves through High-Speed Signals and Grounding, Power Stages and Magnetics, Analog Precision and Stability, and Thermal Management and Compliance.
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Key ideas in Real-World Circuit Design
- A trace behaves as an electrically long transmission line when signal rise time (tr) is shorter than the two-way propagation delay (2 * tpd)
- On FR4, propagation delay is roughly 6 to 7 ps/mm (15 cm/ns), giving a ~1.33 ns round-trip flight time for a 10 cm line
- When round-trip time exceeds rise time, reflections cannot settle during transition edges, requiring distributed transmission line modeling rather than lumped LC analysis
- Above critical cutoff frequencies (typically tens of kHz), return current pathing is dominated by inductive reactance (omega * L) rather than ohmic resistance
- Mutual inductance between signal and return forces high-frequency return current to crowd directly beneath the signal trace to minimize total loop area and enclosed magnetic flux
- Series termination places a resistor at the driver such that R_source + R_driver equals Z0, absorbing receiver-reflected waves without drawing steady-state DC current
- Parallel termination places R = Z0 at the receiver, terminating the initial wave immediately at the cost of continuous DC dissipation
- AC termination inserts a series capacitor with the parallel resistor to block DC dissipation while presenting matching impedance at high-frequency edge transitions
- A split forces high-frequency return current to divert around the void, creating a large parasitic inductive loop that radiates electromagnetic fields
- The sudden impedance discontinuity at the boundary causes reflection, ringing, and edge degradation
- A via barrel introduces excess series inductance (typically 0.5–1 nH) while antipads and pads introduce parasitic capacitance
- Placing an adjacent ground stitching via within close proximity maintains a continuous reference loop for the vertical transition
- Backdrilling unused via stubs eliminates resonance and reflection notches caused by open-circuit stub reflections
- High-frequency return currents travel directly underneath the trace along the path of least inductance
- Crossing a plane discontinuity forces return current into an expansive loop around the moat, creating a slot antenna that radiates and picks up EMI
- A continuous, unbroken reference plane contains return currents directly beneath their signal lines
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives Real-World Circuit Design the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
On standard FR4, signals travel at roughly 15 cm/ns (6 to 7 ps/mm). What is the round-trip flight time down and back along a 10 cm trace?
Get it right to open this lesson and 25 more in the app.
Where Real-World Circuit Design takes you
Move past idealized textbook schematics into the physics of high-speed signals, control loop stability, and electromagnetic compliance. Master parasitic management, noise reduction, and robust power delivery.
- 1
High-Speed Signals and Grounding
- Taming Signal Reflections and Return Paths
- Mixed-Signal Grounding and Data Conversion
- 2
Power Stages and Magnetics
- Switch-Mode Power Converter Dynamics
- Inductor and Transformer Physical Limits
- 3
Analog Precision and Stability
- Feedback Loop Stability and Compensation
- Low-Noise Weak-Signal Conditioning
- 4
Thermal Management and Compliance
- Thermal Spreading and Semiconductor Limits
- Electromagnetic Compatibility and Parasitics
4 sections · 8 units · 26 levels. Built to play, not to enroll.
You pick the voice
Real-World Circuit Design is taught in the The Bestie style: your friend who just gets it. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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Start Real-World Circuit Design today.
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