PCB Testing
Assembled PCB Testing
Testing Parameters
- Functional parameters – verify intended operations
- Performance parameters – speed, accuracy
- Electrical parameters – voltage, current, resistance
- Environmental parameters – temperature, humidity
Basic Electrical Rules
- Ohm’s Law
- Kirchhoff’s Law
- Faraday’s Law of Induction
Use of Test Equipment
- Current, Voltage, Frequency, Resistance measurement
- CRO, DSO usage
Component Testing
- Diodes, Transistors, Resistors, Capacitors
- Relays, Coils, LEDs, Transformers
- ICs (Digital & Linear)
PCB Level Testing
- Open circuits
- Short circuits
- Components out of tolerance
- Checking & troubleshooting basics
Tools & Techniques
- Crocodile clips, cleaners, sprays, CRO probes
- Logical troubleshooting methods
- Component, Board & System level troubleshooting
Testing Methods
- Cold Test & Hot Test
- Fault analysis in electronic circuits
- ESD role and prevention
- Generic & specific safety precautions
Systematic Troubleshooting
- Identify the symptoms
- Gather information
- Clean the PCB
- Check power supply & connections
- Test the circuit, isolate problems
- Replace/repair faulty components
- Final repair testing
Steps to Test a Faulty Circuit
- Initial Safety & Visual Observation
- Check for Shorts (continuity test)
- Power Supply Test (bench PSU, current limiting)
- Thermal Check (touch/IR camera)
- Signal Tracing with CRO/Logic Analyzer
Advanced Debugging
- Divide & Conquer (isolate circuit sections)
- Component-Level Testing (diodes, resistors, capacitors, ICs)
- Compare with a known good board
- Firmware/Software check (boot pins, configs)
- Document findings & repair notes