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What is the reason for inrush current?
Inrush current is the instantaneous high input current drawn by a power supply or electrical equipment at turn-on. This arises due to the high initial currents required to charge the capacitors and inductors or transformers. The inrush current is also known as the switch–on surge, or the input surge current.
How do I check my inrush current?
- With the device to be tested turned off, turn the meter’s dial to .
- Center the jaw or flexible probe around the device’s live wire.
- Push the inrush button, on the face of the meter.
- Switch on the device. The inrush current (spike) is displayed in the meter’s display.
Where does the inrush current come from in a power supply?
Inrush current is the instantaneous high input current drawn by a power supply or electrical equipment at turn-on. This arises due to the high initial currents required to charge the capacitors and inductors or transformers.
How does high inrush current affect a microcontroller?
High inrush current affects the source power supply. Often high inrush current drops the source voltage and results in a brownout reset for microcontroller-based circuitry. In few cases the amount of current supplied to the circuit gets beyond the acceptable maximum voltage of the load circuit, causing permanent damage to the load.
Are there any ways to limit the inrush current?
Limiting inrush currents. The two commonly used protection methods are, the passive, where a resistive current limiting device is connected in series with the supply, and the active which uses an electronic circuit consisting of resistors, a switching device and a control circuit.
How does the temperature affect the inrush current?
At ambient temperature the NTC device exhibits a high resistance, when the power is turned-on, the high resistance limits the amount of inrush current flowing into the circuit. As the current flows, the thermistor temperature increases thereby reducing the resistance significantly.