Round 6 : Noise/ripple
Green : current probe in AC
Red : voltage probe on the DC load not the battery
DMM is K2000 for only 4KHz of BW while we have 22Khz of noise ripple
Configuration 1 : CC 30A range /12.5A set point / RIS/FAL : 2.5A/µs / averaging 2^8
Ipp : 390mA Irms =125 mA
Configuration 2 : CC 30A range /12.5A set point / RIS/FAL : 0.01A/µs
Now we have 110 Ipp for 22.6 mA rms still for 12.5A. We always notice 22.6Khz of noise ripple frequency
Configuration 3 : CC 30A range /9.9A set point / RIS/FAL : 0.004A/µs
We are in the noise of the probe. With a DMM (Fluke 45 calibrated) we have around 4mA rms of noise ripple
Configuration 4 : CC 30A range / 1A set point / RIS/FAL : 2.5A/µs
Real : 0.999 A for 16 mArms of ripple noise on Keithley 2000
Configuration 5 : CC 30A range /1A set point / RIS/FAL : 0.004 A/µs
Real 0.999 for 2.3 mArms of ripple noise on Keithley 2000
Configuration 6 : CC 5A range /1A set point / RIS/FAL : 0.004 A/µs
Real 0.999A Curiously, the ripple noise is higher on the 5A range and the value is around 4.7 mA rms
Configuration 7 : CC 30A range /0.4A set point / RIS/FAL : 0.004 A/µs
Real : 0.399A for 2.1mA rms of noise ripple On the 5A range the noise is slightly higher at 2.5mA
Configuration 8 : CC 5A range /0.05A set point / RIS/FAL : 0.004 A/µs
Real : 49.X mA (X not stable ) for 1.9mA of noise
Configuration 9 : CC 5A range / 3A set point / RIS/FAL : 2.5 A/µs
Real: 2.998 A for 3.001A on SDL with 18mA of noise ripple (limitation du to DMM) hereunder real waveforms on a resistor of around 1 Ohm in yellow and my curent probe in green :
The noise depends on the range (5/30) , the rise rate, the fall rate and the output current. It can rise to
4/5% of the setpoint (a Keithley DC load doesn't exceed 5 mArms on the full range)