Differences between FCT test and ICT test

Testing Objectives and Targets

FCT Testing:

• Objective: Primarily used to test a product’s parameters during normal operation, verifying whether the product functions correctly.
• Target: Conducted after ICT testing, focusing on circuit boards or products that have passed ICT, testing functionality under power.

ICT Testing:

• Objective: Primarily used for electrical testing of the circuit board (PCBA), checking for component and soldering faults.
• Target: Performed in the next process after the circuit board has been soldered, directly testing the components and solder joints.

Testing Principles and Methods

FCT Testing:

• Principle: Provides the Unit Under Test (UUT) with a simulated operating environment (stimuli and load) to make it work in various designed states, gathering parameters to verify its functionality.
• Method: Applies appropriate stimuli and measures the output response to see if it meets requirements. Common control methods include MCU control, embedded CPU control, PC control, and PLC control.

ICT Testing:

• Principle: Uses a bed-of-nails fixture to contact the components on the circuit board, measuring the parameters of resistors, capacitors, inductors, and checking for open/short circuits at solder points.
• Method: Connects to predefined test points on the board through the bed-of-nails fixture, performing open circuit, short circuit, and component functionality tests, checking the electrical and soldering conditions of all parts.

ICT Testing

Testing Stages and Processes

FCT Testing:

• Typically follows ICT testing as a later stage in the product testing process.
• Reduces the need to reposition the product after ICT, improving testing efficiency.

ICT Testing:

• Conducted immediately after the soldering process of the circuit board.
• Faulty boards (e.g., components soldered in reverse, short circuits) are repaired on the soldering line to allow for timely identification and correction.

Advantages and Limitations of Testing

FCT Testing:

• Advantages: Can thoroughly validate product functionality, ensuring normal operation in real working conditions.
• Limitations: High testing complexity, requiring simulation of real operating environments, with high demands on testing equipment and conditions.

ICT Testing:

• Advantages: Fast testing speed, capable of quickly pinpointing faults, improving circuit board quality and reliability.
• Limitations: Testing precision may be somewhat limited, and certain subtle faults may not be accurately detected.