Such faults are static. The cause of power failure is mostly caused by open circuit of power line or ground wire, incorrect wiring or poor contact, or it may be caused by the input voltage of the instrument equipment or the circuit board's own power component components exceeding the allowable deviation, and the output voltage exceeding the allowable deviation caused by the power component's own circuit failure (such as abnormal voltage rise or decrease).

Such faults include open circuits caused by loose resistor end caps, open or open capacitors, changes in capacitance or resistance values, burned resistors, etc. Changes in resistance values may cause faults such as blurred logic values, and changes in capacitance values may cause faults such as poor decoupling, oscillator frequency changes, and failure to start equipment such as motors.