The time delay circuit 130 such as a resistive/capacitive circuit, inserts a predetermined delay before the current switch opens to prevent false shut downs due to normal current surges characteristic of electromechanical devices. That is, when the current sensor senses a current above a threshold, the time delay circuit provides a delay period for the current to drop off below the threshold before the switch is opened. The time delay, on the order of milliseconds, can be adjustable for the device or situation.

The current switch 120 interrupts current based on the current sensor 110 determination that the current draw exceeds a threshold. The current switch 120 such as a power field effect transistor (FET) disconnects the power source 90 before a saturation induced excessive current draw damages the device 80.

With reference to FIG. 3, a circuit diagram shows an embodiment in which the device 80 includes a non-invasive blood pressure (NIBP) monitor 200. The power supply 90 outputs a 12V direct current (DC). The direct current may be directly from a battery or may be converted from a standard wall outlet (110V or 220V AC) to 12V direct current. The protection mechanism 100 is placed between the power source 90 and the protected device 80, particularly a motor and solenoid assembly of the NIBP monitor 200. With the protection mechanism 100, the NIBP monitor which would have been damaged at 400 gauss can be exposed to magnetic fields 40 of 30,000 gauss or more without damage.