extrait du manuel de la dernière version (1.11K)
5.3.7 Voltage loss after a load pulse, Vloss
With the measurement of capacitors with big capacity values the voltage loss after the loading is
analysed. The reached load voltage is lost with electrolytic capacitors after a short periode. This
voltage loss can be caused by a parallel connected resistor. But I assume, that this voltage loss
of electrolytic capacitors is caused by a internal load dispersion directly after the load pulse.
By loading the capacitors with the 470k resistor, as it is done for little capacity values, this dispersion
is already done after switching off the current. No voltage loss is detectable for this case. But if you
load the same capacitor with a short current pulse, you can also detect the voltage loss for capacitors
with lower capacity. The same effect with lower loss can also be noticed for ceramic type capacitors.
I have noticed, that capacitors with more than some % voltage loss are suspect. Especially noticable
with respect to the voltage loss are older paper type capacitors, which are for other measurement a
problem too. Some measurement examples will be shown in the following table.
capacitor Nenn- PeakTech Voltcraft PeakTech Transistortype capacity LCR 2170 M2650-B 3315 Tester
paper4700pF 6.75-10.36nF 8.00nF 25.40nF 10.71nF Q=2.5-32 Vloss=11%
paper 6800pF 9.40-11.40nF 10.41nF 23.30nF 11.65nF Q=5-25 Vloss=5.0%
unknown 4700pF 5.85-6.33nF 6.12nF 6.90nF 6225pF Q=16-87 Vloss=1.7%
foil 7870pF 7.86-7.87nF 7.95nF 7.95nF 7872pF Q= >1540 Vloss=0%
paper 22000pF 37.4-57.5nF 52.8nF 112nF 118.5nF Q=2.5-32 Vloss=12%
foil 22600pF 22.4-22.5nF 22.57nF 22.69nF 22.54nF Q= >1540 Vloss=0%
paper 100nF 144-256nF 177nF 318nF 529.7nF Q=2.6-28 Vloss=12%
ceramic 100nF 97.7-102nF 103.7nF 103.3nF 103.1nF Q=90-134 Vloss=0.1%
foil 100nF 98.0-101nF 101.4nF 102.2nF 101.6nF Q=58-700 Vloss=0%
In this table you will nd, that the capacity of all foil type capacitors can be measured by all
intruments with good precision. The capacity values and the quality factor Q of the PeakTech LCR
meter are minimum and maximum values of the measurements in the frequency range 100Hz to
100kHz. At all examples in the table the voltage loss Vloss of the TransistorTester is big, if the
capacitors have a low quality factor. Only in this case the dierences of the capacity measurement
results are also big. The TransistorTester can only determine the voltage loss, if the measured