About Uninterruptible Power Supplies (UPS)

Sinewave vs Simulated Sinwave - Which is Best?

A sinewave output is the optimum waveform for electronic equipment. The incoming AC line is a sinewave, thus electronic equipment expects to see this type of waveform. A sinewave is the most expensive output form for UPS manufacturers to produce due to more complex circuitry and components. All Minuteman UPSs that produce a sinewave output go one step further by producing a synchronized sinewave. This feature eliminates the problem of an out of phase wave at the output. The Continuous Power, XRT, and PowerMind series from Minuteman provide a true sinewave output.

A pulse width modulated squarewave (also called simulated sinewave) is considerably easier to produce in a UPS. This type of waveform is quite suitable for virtually all electronic business equipment. Minuteman's Pro series produces a simulated sinewave output.

Waveform Comparison Chart


Sine waveform - Minuteman UPS
Sine wave
Sine Wave - Utility Power & High End UPSs
The pure sine wave is the ideal wave form for both equipment performance and longevity, and the form you typically receive from utility power providers.  Electrical energy smoothly alternates between negative and positive, allowing equipment to operate without undue stress at a consistent voltage with few high frequency harmonics.  High end UPSs such as Minuteman's Endeavor series produce true sine wave power through an AC-DC-AC conversion process, while the EnterprisePlus Series use automatic voltage regulation to produce it.
Great performance
Safe for sensitive equipment
No effect on equipment longevity
Increased cost

Modified Square Wave - Minuteman UPS
Simulated Sine / Modified Square Wave
Simulated Sine or Modified Square Wave Form
The modified square wave is a compromise between cost and power quality.  While not ideal, the modified square wave has peak voltages close to a pure sine wave, and an overall shape which closely resembles this ideal form.  This allows the modifed square wave to behave favorably with connected equipment, while keeping manufacturing costs close to that of square wave equipment.  Many of Minuteman's standby and line interactive UPS models make use of this architecture to maintain a balance between performance and cost.
Similar performance to utility power
Close overall voltage output
Manufacturing cost significantly less than true sine wave
Can cause irregular operation on highly sensitive equipment

Square Wave - Minuteman UPS
Square wave
Square Wave - Low End Power Equipment
Square waves are typically produced by lower end power equipment, and by nature put greater strain on connected equipment.  Peak voltage of this wave is lower than a sine wave of the same total power output, and the waves can also contain dangerous high frequency harmonics not present in a sine wave.  Equipment running on square waves can experience operational problems, including heat build up, and possible premature failure,
Significant manufacturing cost savings
Decreased equipment longevity
Equipment operation problems

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