dual power supply with soft power switch

Soft power for a large transformer is implemented by using a series resistance of 100 ohms at 10 watts, or alternatively, two resistors of 47 ohms at 5 watts each in the primary circuit. The resistance is bypassed by a relay after approximately 1.5 seconds, preventing a sudden surge of current during power-up. A Zener diode can be adjusted to accommodate various voltage relays. The schematic diagram originates from a circuit related to a dual power supply with a soft power switch. Further details can be found on the related page discussing the power supply circuit diagram.

The described soft power circuit is designed to manage the inrush current that occurs when a large transformer is energized. Inrush current can lead to potential damage to components and cause circuit instability. By incorporating a series resistor of 100 ohms, or two 47-ohm resistors in parallel, the circuit limits the initial current flow, allowing for a gradual increase in voltage across the transformer. This method enhances the longevity and reliability of the transformer and associated components.

The relay plays a critical role in the operation of this soft power circuit. After a predetermined delay of approximately 1.5 seconds, the relay activates and shorts the series resistance. This transition allows the transformer to operate under normal conditions without the resistive drop, thus improving efficiency. The use of a Zener diode in the circuit provides versatility, as it can be set to accommodate different voltage levels for various relay types. This adjustability ensures compatibility with a range of transformers and power supply configurations.

The dual power supply with a soft power switch design further enhances the functionality of the circuit by allowing for controlled power delivery to multiple outputs. This design is particularly beneficial in applications requiring stable voltage levels and minimal electrical noise, making it suitable for sensitive electronic devices and systems. The schematic diagram associated with this power supply circuit provides a visual representation of the components and their interconnections, aiding in both understanding and implementation.Soft power for a large transformer is made by taking the series resistance of 100 ohms/10 watt or two resistors 47 ohm / 5 watts in the primary circuit, the resistance is shorted by the relay after ± 1. 5 seconds. This avoids a sudden use of the current during power up. A Zener diode can be adjusted to allow theuse of various voltage relay. The schematic diagram come from circuit: Dual Power Supply with Soft Power Switch power supply. Go to that page to read the explanation about above power supply related circuit diagram. 🔗 External reference