Keysight E3630A, Operating And Service Manual

Page: 56 / 71

5 Service Information
56 Keysight E3630A Operating and Service Manual
Common mode current (CMI)
Definition : Common mode current is that AC current component which exists
between any or all supply or output lines and chassis ground.
To measure the common mode current:
1 Connect the full load for +6 V output.
2 Connect a 100 k W resistor(R
S
) and a 2200 pF capacitor in parallel between
common terminal (COM) and chassis ground.
3 Connect the DVM across R
S
.
4 Turn on the supply.
5 Record the voltage across R
S
and convert it to current by dividing this voltage
by R
S
.
6 Check that the current is less than 1 m A.
Load transient response time
Definition:
This is the time for the output voltage to return to within a specified
band around its voltage following a change from full load to half load or half load
to full load.
To measure the load transient response time:
1 Connect the test equipment across the output of the +20 V supply as shown in
Figure 5-5 , but replace the DVM with the oscilloscope. Operate the electronic
load in constant current mode.
2 Turn on the supply.
3 Turn up output voltage to the full rated value.
4 Set the electronic load to transient operation mode between one half of
supply's full rated value and supply's full rated value at a 1 KHz rate with 50%
duty cycle.
5 Set the oscilloscope for AC coupling, internal sync and lock on either the
positive or negative load transient.
6 Adjust the oscilloscope to display transients as in Figure 5-7 .