The purpose of the test is to check the presence of the component and the accuracy of the capacitor value, verifying any anomalies.

The test consists in injecting a direct current at the terminals of the capacitor and measuring the time that the voltage ramp takes to cross a window consisting of two voltage levels.

     Δt = C · ΔV / I

   ΔtT (1 + TOLmin) < ΔtM < ΔtT (1 + TOLmax)

where:

 C capacity

 I injected constant current in the capacitor

 ΔV voltage window to measure time t

 Δt time interval needed to switch the voltage from V1 to V2

 ΔtT theoretical time

 ΔtM measured time

 TOLmin minimum tolerance specified

 TOLmax maximum tolerance specified

The use of a measurement with 2 wires (+ guarding) is recommended.