Technical Terms

When turning on a regulated DC power supply, the Inrush current flows higher than the rated current instantaneously.

At turn-on, a high current exceeding the rated value flows through the circuit immediately, reaching the peak current value. The current value then drops and gradually converges to the rated current value. The inrush current may put a lot of stress on the circuit and be regarded as an overload or short circuit. In some cases, it may cause the breaker to trip or the voltage to drop, and shut down the equipment connected.

Inrush currents could cause by several reasons. In the case of equipment with capacitors, a high current may flow because the capacitors must first be charged. Regarding the devices with filaments, as the resistance of the filament is low before heating the filament, there is highly possible the current flowing gets very high.

Matsusada Precision provides a broad product lineup of power supplies to protect the circuit from the inrush current occurrence. Also, our products are available to support supply power while adjusting to operating within their ratings.