Sinrace Power Supply Technology (Shenzhen) Co., Ltd.

XP Power has introduced the SHP650 and MHP650 series of single-output high-power-density fan-cooled AC/DC power supplies.

The MHP650 range meets the IEC60601-1 safety specification for medical equipment, while the SHP650 range compiles with the IEC60950 standard for IT and industrial equipment.

Both series are highly efficient - typically 86 per cent - and have a high power density of 8.2W/in3.

Three mechanical mounting formats are available to provide design-in flexibility.

The power supply in a PC supplies various voltages to internal devices in a computer via power connectors. These voltages don't have to be exact but they can only vary up or down by a certain amount, called a tolerance.

Prior to 1980 or so, power supplies tended to be heavy and bulky. They used large, heavy transformers and huge capacitors (some as large as soda cans) to convert line voltage at 120 volts and 60 hertz into 5 volts and 12 volts DC.

PC power supplies are often ideal for other purposes but the required loads represent wasted power. So, it would be nice to be able to eliminate them. Unfortunately, it probably isn't easy to modify a PC power supply so less/no load is needed for regulation. However, it is worth testing a supply to see how low you can actually go on the loads - many WILL regulate the +5 with no load on the +12 but probably not the reverse. While 20 percent load is often recommended, 5 percent or less may work just fine. And, some don't need any additional loads on either output (they will probably include a minimal load resistor internally).

Changing the input voltage of a switch mode power supply
Would it be possible to modify a power supply designed for operation on 120 VAC for use overseas where the power is 240 VAC?
There are many factors involved in changing a power supply unless it is designed for dual voltage or autoswitching. They saved a few cents if it is not easily switched, what can I say?

Startup is the most stressful time for a typical switchmode power supply. The output filter capacitors as well as the load must be driven while the input voltage is changing - possibly wildly. With careful design, these factors can be taken into consideration. Not all power supplies are designed carefully or thoroughly tested under all conditions. When power is restored, surges, dips, brownouts, and multiple on-off cycles are possible. This is why it is always recommended that electronic equipment be unplugged until power has been restored and is stable.