The role and application fields of leakage current in medical testing equipment

The leakage current mode of medical testing equipment is a key function used to detect the insulation performance of medical devices. By simulating the human impedance network to measure current values, it ensures that the equipment does not pose a risk of electric shock to patients and operators in normal or faulty states.
The core role of leakage current mode
This mode mainly measures three types of currents:
Ground leakage current: the current of the power supply through the protective grounding conductor
Shell leakage current: the current flowing from the touchable part of the device to the ground through the human body
Patient leakage current: the current flowing through the patient to the ground in the application part (unique to medical equipment)
Principle of Technical Implementation
The test uses a simulated human impedance network (MD), which includes components such as a 1k Ω resistor and a 0.015 μ F capacitor, to accurately simulate the impedance characteristics of the human body at different frequencies. The instrument measures the effective value of leakage current through this network, with an error not exceeding 5%.

The leakage current mode of medical testing equipment simulates the human impedance network to accurately measure the risk of electric shock that the equipment may cause to patients or operators. It is mainly applied in the following scenarios:
1. Production and R&D process
This is the most core application scenario. Medical devices must undergo strict safety testing before leaving the factory, and the leakage current mode can comprehensively detect ground leakage current (current flowing into the protective grounding wire through insulation in the power supply part), shell leakage current (current flowing into the ground through an external path that can touch the shell), patient leakage current (current flowing from the application part through the patient into the ground), and patient auxiliary leakage current (current flowing through the patient between application parts without producing physiological effects). For example, production lines for devices such as heart monitors, X-ray machines, CT scanners, etc. will use this mode for safety verification.
2. Regular maintenance of hospital equipment
Hospitals regularly conduct electrical safety testing on medical equipment in use, with leakage current mode being a key component. It can promptly detect abnormal leakage current caused by equipment insulation aging, moisture or local defects, and prevent medical accidents caused by equipment failures.
3. Equipment troubleshooting
When there is a suspected electrical safety issue with medical equipment, such as the shell being live or the presence of inductors during operation, the leakage current mode can quickly locate the fault point and determine whether it is a power problem, poor grounding, or internal insulation damage.
4. Standard compliance verification
This mode is used to verify whether the equipment complies with medical electrical safety standards such as IEC 60601 and GB 9706, ensuring its safety under different working conditions (such as power polarity switching, protective grounding disconnection)