Robust Hardware: Protection Circuits, ESD and EMC

10 Lektionen in dieser Stufe

1. Writing a Product Requirements Specification
   State functions, interfaces, environment, lifetime, cost and compliance targets in testable form. · Lab: Write the requirements for your field sensor and control node with numbered, verifiable items.
2. Reverse-Polarity and Over-Voltage Protection
   Protect the supply input with a MOSFET, clamp and correctly rated parts. · Lab: Build a protected input stage and prove it survives reversed leads and an over-voltage from the bench supply.
3. Fuses, Resettable Fuses and Current Limiting
   Select protection for fault currents and understand trip time and hold current. · Lab: Short a protected output and record trip and recovery behaviour of a resettable fuse.
4. ESD Protection on Connectors and Buttons
   Explain discharge paths and place suppressor diodes where static enters. · Lab: Zap a protected and an unprotected sacrificial input with a piezo igniter and compare the outcome.
5. Protecting Inputs: Clamps, Series Resistors and Filters
   Make digital and analog inputs tolerant of over-voltage and noise. · Lab: Design an input that accepts 24 V signals safely on a 3.3 V pin and verify it.
6. Driving Inductive and Long-Cable Loads Robustly
   Use snubbers, protected switches and slew control for outputs leaving the board. · Lab: Switch a solenoid or relay coil over a long cable and compare spikes with and without suppression.
7. EMC Basics: Emissions, Immunity and Return Paths
   Describe how circuits radiate and pick up noise and why current loops matter. · Lab: Detect emissions of a switching converter and a motor with a wire-loop probe and a radio receiver.
8. PCB Layout for Low Noise: Loops, Planes and Decoupling
   Apply layout rules for switching regulators, crystals, connectors and ground planes. · Lab: Review your level 30 board against a checklist and lay out revision A of the product board.
9. Pre-Compliance Checks on the Bench
   Find likely problems early with simple probes and comparative measurements. · Lab: Compare emissions before and after adding a ferrite and better decoupling to a noisy board.
10. Failure Mode Analysis and Component Derating
    List what can fail, the effect and the mitigation and select parts with margin. · Lab: Complete a failure-mode table for the product board and check ten parts for derating.

Abschlussprojekt

Revision A of your own product board (a field sensor and control node, the course's final product) designed in KiCad with protected power and I/O, EMC-aware layout, a requirements specification and a failure-mode analysis.

Teile für diese Stufe

• 1 × Computer with KiCad installed
• 2 × P-channel MOSFET logic level
• 1 × TVS diode assortment
• 4 × Schottky diode
• 1 × Zener diode assortment
• 1 × Resettable fuse assortment
• 1 × Fuse holder with fuse assortment
• 1 × Ferrite bead assortment
• 2 × Common-mode choke
• 1 × Ceramic capacitor assortment
• 1 × Resistor assortment 1/4 W
• 2 × ESD protection diode array module or parts
• 2 × Logic-level N-channel MOSFET module
• 1 × Relay module 5 V single channel
• 1 × Bench power supply with current limit
• 1 × Digital multimeter
• 1 × USB logic analyzer 8 channel
• 2 × Perfboard
• 1 × Soldering station
• 1 × Piezo gas lighter for discharge tests
• 1 × Near-field probe set or small wire loop
• 1 × USB software-defined radio receiver
• 1 × ESD wrist strap and mat

In jeder Lektion legst du die passenden Teile direkt in den Warenkorb. Arduino-kompatibel →