High Voltage Leak Detection (HVLD) works by applying a high-frequency, high-voltage signal between two external electrodes placed on opposite sides of the container. These electrodes do not make direct contact with the liquid; instead, a capacitive field is formed between the electrodes and the solution through the container wall. This setup creates two capacitors: C1 and C2. The solution itself acts as a resistor (R), and its conductivity should be ≥1.2 μS to ensure proper signal transmission and accurate detection.

• When the container is properly sealed, the testing system detects only a minimal microcurrent. The insulating layer remains intact, and the circuit behaves as expected, with both capacitors (C1 and C2) in place. This condition is interpreted as a pass.
• If a leak is present, such as a crack or pinhole, the solution makes direct contact with the electrodes. The insulating barrier is compromised, the capacitive effect disappears, and the circuit allows a stronger current to pass. This elevated current indicates a failure.

By comparing the current levels from these two scenarios, the leak testing system can accurately determine whether a container is intact or leaking.