Current Limiting; Electronic Fuse - Hameg Instruments HM8040-3 Manuel

B a s i c s o f p o w e r s u p p i e s
Fig. 3: Parallel operation
Example:
A load draws 0.7 A at 12 V. Each output of the
HM 8040-3 is specified for 0.5 A. In order to supply
the 0.7 A both outputs have to be set to 12 V. Then
the respective output safety terminals have to be
connected in parallel (black to black, red to red).
The load is connected to one of the supplies. By
depressing OUPUT
As a rule one output will supply appr. 500 mA in
current limit mode, the other the balance of
200 mA in voltage control mode.
If you parallel power supplies made by
HAMEG and those of other manufacturers
please make sure that the individual cur-
STOP STOP
rent contributions of the supplies involved
are as equal as possible. HAMEG supplies
are designed for series and parallel opera-
tion. If supplies of other manufacturers are
used in a parallel connection which are not
overload protected damage may occur if
the individual currents are unequal.

Current limiting

means that a maximum current can be set. This
is e.g. useful in order to protect a sensitive test
circuit. In case of an inadvertent short in the test
U
out
U
const
Adjustment of current
Current limit
24
Subject to change without notice
the outputs are activated.
I
I
max
out
circuit the current will be limited to the value set
which will in most cases prevent damage.
The picture shows that the output voltage V
remains stable, while the current I increases until
the current limit selected will be reached. At this
moment the instrument will change from
constant voltage regulation to constant current
regulation. Any further load increase will cause
the current to remain stable while the voltage
decreases ultimately to zero.

Electronic fuse

This feature provides a still better protection of
sensitive loads, especially of such loads which
require more than one voltage: if one current limit
is reached all output voltages will be dis-
connected immediately. In order to turn these
back on the pushbutton OUTPUT
depressed.
out
must be