Electronic Wattmeter
Chapter 4
6.
Check that
it
is now possible to close either
SWA
or
SWv
without producing a significant signal
on
the oscilloscope.
Disconnect the lead to
Pin
22
and turn the instrument the
correct way
up.
Zero the meter with the front panel
control-
check the
correctness of this zero by pressing the meter reverse.
Check that
closing SWA or
SWv
produces
no
measurable
deflection.
7.
Check the sensitivity against a standard dynamometer
wattmeter
by
using the layout connection of
fig
4.11.
A.C.
Supply
Standard Wattmeter
FIG 4.11
Su1table
dummy
load
This connection of the EW604 to a standard wattmeter
as
shown
in
fig
4.11
enables a direct comparison of sensitivities to
be
made without the need for corrections due to internal power
consumption.
Select suitable compatible ranges and use R42
and
R21
in
turn
to
bring the deflection of the EW604 to the same value as the
standard wattmeter.Note that it
will
be
necessary to disconnect
the
external supply when adjusting
R21
(ZERO).
4.3 Component Replacement Table
The EW604
is
generally not critical with regard to component
types but proper performance can
only be expected if
component
replacements are of reasonably similar types.
A brief
general specification of suitable components
is
listed.
28
To Next Page
Loading...
Need help?
General
