The Electronic Load

The Electronic Load
H&H Application Note #8
Non-linear AC current loads with ZSAC series
Power Factor PF
A power factor is defined
whenever the product of
voltage and current does not
equal the actual effective
power.
The power factor can be widely
used therefore and refers both
to the sinusoidal signals and
other signal forms.
cos phi (Displacement Power
Factor)
Cos phi is a special form of
power factor which only applies
when sinusoidal signals are
present, as in the case of
The diagrams below show the
voltage (blue), the current
(red) and the power (green).
inductive and capacitive loads.
Crestfactor (CF)
Defines the ratio of the peak
value to the effective value of a
voltage.
A sinusoidal voltage has crest
factor 1.41.
Function Principles of
Electronic AC Loads
Electronic AC loads function in
principle like direct current loads
with rectifier.
The control voltage needed to
set the load however is not a
static signal as with direct
current but is half wave-shaped
according to the rectified input
voltage.
A sinusoidal AC current is
thereby generated at the input
of the rectifier.
As a result of the rectifier, the
energy in the case of alternating
current loads can flow only in
the load direction and never
back towards the source.
Application Notes ZS PL H&H
ZSLC
watercooled
PMLI
Multi-channel
GTC
Software
ZSLV
Low Voltage
ZSAC
AC
NL
Source-Sink
Definition of the Terms
It is often necessary to apply
non-linear loads to AC voltages.
The terms used; cos phi, crest
factor, power factor etc. can
often lead to confusion.
This Application Note defines
what is possible with the
ZSAC series electronic loads and
what is not.
What Does the Voltage and
Current Waveform Look Like
in Non-Linear Loads
In order to evaluate which loads
are possible with an electronic
load and which are not it makes
sense to look at a few load
cases:
Particular attention is paid to
the direction of the energy flow
because the electronic load can
consume, but cannot generate,
power.
Example 1:
Sinusoidal current without
phase shift
(ohmic load)
CF = 1.41, cos phi = 1
This means that the load can
reflect this case (typical application).
Accessories
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