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## Ripple and Noise Tests

Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.

The FSP Aurum Pro 850 W provided low ripple and noise levels, as you can see in the table below.

 Input Test 1 Test 2 Test 3 Test 4 Test 5 +12VA 39.4 mV 40.4 mV 39.2 mV 45.8 mV 51.4 mV +12VB 37.0 mV 38.2 mV 37.6 mV 47.4 mV 53.4 mV +5 V 14.2 mV 19.2 mV 23.2 mV 27.6 mV 32.8 mV +3.3 V 12.6 mV 15.0 mV 19.2 mV 23.2 mV 27.2 mV +5VSB 12.2 mV 14.0 mV 16.4 mV 18.4 mV 24.0 mV -12 V 38.4 mV 40.4 mV 38.8 mV 43.8 mV 47.4 mV

Below you can see the waveforms of the outputs during test five.

Figure 22: +12VA input from load tester during test five at 850.2 W (51.4 mV)

Figure 23: +12VB input from load tester during test five at 850.2 W (53.4 mV)

Figure 24: +5V rail during test five at 850.2 W (32.8 mV)

Figure 25: +3.3 V rail during test five at 850.2 W (27.2 mV)

Let’s see if we can pull more than 850 W from this unit.

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Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.