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Ripple Measurements
To learn how we measure ripple, please click here.
The following table includes the ripple levels we measured on the AG-850M’s rails. The limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V, and 5VSB).
| Test | 12V | 5V | 3.3V | 5VSB | Pass/Fail |
|---|---|---|---|---|---|
| 10% Load | 8.2mV | 11.7mV | 13.8mV | 26.9mV | Pass |
| 20% Load | 14.0mV | 14.0mV | 15.9mV | 35.4mV | Pass |
| 30% Load | 17.1mV | 14.9mV | 17.7mV | 35.4mV | Pass |
| 40% Load | 18.6mV | 16.5mV | 18.4mV | 38.1mV | Pass |
| 50% Load | 21.5mV | 17.6mV | 20.7mV | 51.7mV | Fail |
| 60% Load | 23.0mV | 19.0mV | 22.0mV | 51.2mV | Fail |
| 70% Load | 25.0mV | 20.4mV | 23.7mV | 60.2mV | Fail |
| 80% Load | 26.7mV | 22.4mV | 25.5mV | 68.5mV | Fail |
| 90% Load | 30.7mV | 24.1mV | 26.9mV | 66.0mV | Fail |
| 100% Load | 37.3mV | 28.7mV | 31.7mV | 70.1mV | Fail |
| 110% Load | 38.7mV | 28.9mV | 31.8mV | 74.6mV | Fail |
| Cross-Load 1 | 15.0mV | 31.4mV | 28.7mV | 41.6mV | Pass |
| Cross-Load 2 | 37.0mV | 24.5mV | 27.8mV | 76.8mV | Fail |
The first sample we tested had a problem with its 5VSB rail, where ripple was clearly out of control. Since we had a second sample at our disposal, we tested its ripple and measured significantly better performance. The following table shows the second AG-850M sample's ripple results.
| Test | 12V | 5V | 3.3V | 5VSB | Pass/Fail |
|---|---|---|---|---|---|
| 10% Load | 8.5mV | 13.2mV | 12.9mV | 5.6mV | Pass |
| 20% Load | 16.1mV | 15.6mV | 15.4mV | 5.8mV | Pass |
| 30% Load | 21.4mV | 17.0mV | 17.6mV | 6.5mV | Pass |
| 40% Load | 25.7mV | 18.3mV | 19.3mV | 7.4mV | Pass |
| 50% Load | 26.6mV | 20.5mV | 21.0mV | 8.9mV | Pass |
| 60% Load | 30.4mV | 22.1mV | 23.0mV | 9.9mV | Pass |
| 70% Load | 36.4mV | 23.9mV | 25.7mV | 10.6mV | Pass |
| 80% Load | 39.2mV | 26.7mV | 29.2mV | 11.8mV | Pass |
| 90% Load | 43.1mV | 28.7mV | 31.0mV | 13.2mV | Pass |
| 100% Load | 53.5mV | 32.7mV | 36.3mV | 17.5mV | Pass |
| 110% Load | 56.6mV | 34.4mV | 37.0mV | 17.8mV | Pass |
| Cross-Load 1 | 16.1mV | 30.0mV | 30.8mV | 12.0mV | Pass |
| Cross-Load 2 | 50.4mV | 25.7mV | 29.1mV | 16.2mV | Pass |
The second sample fares much better in our 5VSB measurements. But that's not the case for all rails, particularly the always-critical +12V one.
Ripple Oscilloscope Screenshots
The following oscilloscope screenshots illustrate the AC ripple and noise registered on the main rails (+12V, 5V, 3.3V and 5VSB). We usually set 0.01 V/Div (each vertical division/box equals 0.01V), but in some cases we use a smaller setting as well, if the registered ripple is very low.
Ripple At Full Load
Ripple At 110-Percent Load
Ripple At Cross-Load 1
Ripple At Cross-Load 2
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