A humidity indicator card is a practical tool that monitors the relative humidity of a confined space through color changes. It is widely used in moisture-proof packaging for moisture-sensitive products such as electronic components, IC chips, and precision instruments. Its use is simple and intuitive, but attention to operational details is necessary to ensure accuracy.
1. Basic Usage Steps
Place the Card: Place the humidity indicator card inside the sealed packaging to be monitored, such as a moisture-proof bag (MBB), vacuum packaging, or a desiccant box.
Use Desiccant: Ensure sufficient desiccant (such as silica gel) is placed inside the packaging to maintain a low-humidity environment. Use the card to determine if the desiccant has deteriorated.
Seal the Packaging: After sealing, keep the packaging intact to prevent air leakage or damage, and prevent external moisture from entering.
Observe the Color: Before opening the packaging, observe the color change of each dot on the indicator card:
Blue: Indicates that the current humidity is lower than the value marked at that point; the environment is dry and safe.
Pink: Indicates that the humidity has reached or exceeded the corresponding value; there is a risk of moisture absorption.
Example: If the 10% RH dot turns pink, it indicates that the humidity inside the packaging is ≥10%, which may affect the reliability of moisture-sensitive devices (MSDs).
2. Reading and Judgment Criteria
Each dot is marked with its corresponding relative humidity value (e.g., 5%, 10%, 60%). A color change indicates that the threshold has been reached.
If multiple dots change color, the earliest changing dot is used as the reference.
If all black circles remain blue after opening, it indicates good sealing and effective desiccant; any unused material can be resealed.