EasyManua.ls Logo

HP 200 Series - Page 2

HP 200 Series
7 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Loading...
9ttAbuiciiaM&
200
SERIES
RESISTANCE-TUNED
OSCILLATORS
The
200
series
Resistance-tuned
Oscillators
includes
the
Model
200A
with
a
frequency
range
of
35
cps
to
35,000
cps
and
I
watt
output,
the
Model
200B
with
a
frequency
range
of
20
cps
to
20,000
cps
and
I
watt
output,
the
Model
200C
with
a
frequency
range
of
20
cps
to
200
KC
and
100
milliwatts
output,
and
the
Model
200D
with
a
frequency
range
of
7
cps
to
70
KC
and
100
milliwatts
output.
These
units
consist
of
an
oscillator
section
and
a
power
amplifier
section
with
the
necessary
voltage
supplies.
DESCRIPTION
1-
1
General:
The
oscillator
section
is
a
two
stage
re
sistance-coupled
amplifier
over
which
both
positive
and
negative
feedback
are
applied.
The
positive
feed
back
network
is
a
frequency
selective,
resistance
con
denser
combination
which
is
used
to
control
the
fre
quency
of
oscillation.
Negative
feedback
is
used
to
stabilize
the
operation
of
the
circuit.
The
amount
of
negative
feedback
is
determined
by
a
resistance
net
work,
one
element
of
which
is
non-linear.
This
element
controls
the
amount
of
feedback
in
accordance
with
the
amplitude
of
oscillation
and
consequently
maintains
the
proper
operating
point
in
the
system.
1-
2
Output
Amplifier
Models
2OOA
and
2OOB:
The
Models
200A
and
200B
have
a
two
stage
power
am
plifier
with
a
transformer-coupled
output
following
the
oscillator
section.
Feedback
is
used
in
the
power
ampli
fier
to
eliminate
distortion
and
to
provide
good
fre
quency
response.
This
amplifier
is
designed
to
deliver
I
watt
of
audio
power
into
a
500
ohm
resistance
load
over
the
major
portion
of
the
frequency
range.
Special
output
impedances
are
supplied
on
order
and
in
this
case
the
output
impedance
is
marked
on
the
panel
of
the
instrument.
The
internal
impedance
of
the
output
system
is
approximately
50
ohms
so
the
output
voltage
is
not
critical
with
load
resistance.
A
load
resistance
of
600
ohms
may
be
used
with
only
small
loss
in
available
power.
A
load
resistance
less
than
500
ohms,
however,
will
cause
an
abnormal
drop
in
output
voltage
at
fre
quencies
above
10,000
cps.
1-3
Output
Amplifier
Models
2OOC
and
2OOD:
The
Models
200C
and
200D
have
a
two
stage
resistance-
coupled
output
amplifier.
Feedback
is
used
in
this
amplifier
to
eliminate
distortion
and
to
provide
a
good
frequency
response
over
the
wide
frequency
range.
This
amplifier
is
designed
to
deliver
100
milliwatts
into
a
1000
ohm
resistance
load
over
the
major
portion
of
the
frequency
range.
The
infernal
impedance
of
this
amplifier
is
approximately
50
ohms
at
400
cps
and
therefore
the
output
is
not
critical
with
load.
Load
resistances
less
than
1000
ohms
will
tend
to
increase
the
distortion
at
full
output
but
otherwise
will
not
affect
the
operation.
OPERATING
INSTRUCTIONS
2-1
Initial
Adjustments:
This
oscillator
has
been
carefully
tested
and
adjusted
before
leaving
the
fac
tory
and
no
further
adjustments
should
be
necessary.
Before
turning
on
the
power
the
unit
should
be
checked
to
make
sure
the
tubes
are
secure
in
their
sockets
and
the
Mazda
lamp
«s
screwed
in
tightly.
Ordinarily
a
warm-up
period
is
not
required.
However,
when
the
unit
is
first
put
into
operation
or
when
it
has
been
standing
idle
for
a
long
time
the
oscillator
should
be
allowed
to
run
for
ten
or
fifteen
minutes
before
if
is
used.
2-
2
Frequency:
The
main
dial
located
in
the
center
*
of
the
panel
is
calibrated
directly
in
cycles
per
second
for
the
lowest
frequency
range.
The
reading
of
this
dial
is
multiplied
by
the
factor
indicated
on
the
range
switch
at
the
left
side
of
the
panel.
2-
3
Output:
The
output
voltage
is
controlled
by
the
amplitude
control
at
the
right
side
of
the
panel.
This
control
is
ahead
of
the
output
amplifier.
When
very
small
audio
vol+ages
are
required
it
is
good
practice
to
use
an
attenuator
between
the
oscillator
and
the
equip
ment
being
driven.
This
will
help
keep
the
hum
level
far
enough
below
the
audio
signal.
The
oscillator
has
been
adjusted
to
deliver
more
than
rated
power
info
the
load.
Because
of
this
ad
justment
the
output
wave
may
show
some
distortion
when
the
amplitude
control
is
open.
This
condition
is
normal
and
when
low
distortion
is
required
the
oscil
lator
should
be
operated
at
rated
output
or
slightly
below.
2-4
Power
Supply:
The
oscillator
is
designed
to
oper
ate
on
115
volts,
50-60
cps.
MAINTENANCE
3-
1
General:
For
proper
operation
both
the
frequency
calibration
and
the
distortion
level
in
the
output
should
be
periodically
checked.
Also
the
unit
should
be
thor
oughly
cleaned
and
a
drop
of
light
oil
should
be
applied
to
the
bearing
on
the
main
dial
shaft.
3-
2
Calibration:
To
adjust
the
tracking
of
the
main
frequency
selecting
dial,
a
standard
source
of
frequency
must
be
used
for
comparison.
Set
dial
to
200
and
range
switch
to
XI0.
Note
output
of
oscillator
at
20
on
dial
(200
cps.)
then
set
to
200
on
dial.
Adjust
oscillator
fre
quency
to
2000
cps.
by
means
of
Cl
(see
diagram
of
chassis
arrangement)
at
the
same
time
adjust
the
voltage
output
to
be
equal
to
that
obtained
at
20
on
the
dial
by
the
compensating
condenser
(C6
—
Model
200A,
B;
C8
—
Model
200C,
D).
This
requires
some
maneuvering
as
the
settings
are
interdependent.
Check
output
at
20
again
to
make
sure
it
has
not
changed.
If
it
has
changed,
readjust
output
and
frequency
at
200
to
match.
The
Models
200A
and
200D
differ
only
in
their
main
dial
settings
for
oscillator
output
and
frequency
adjust
ment.
These
are
35
(350
cps.)
and
350
(3500
cps.)
for
the
200A;
the
200D
settings
are
7
(70
cps.)
and
70
(700
cps.).
These
adjustments
are
all
made
from
the
bottom
be
cause
the
final
calibration
is
correct
only
when
the
dust
cover
is
in
place.
If
the
instrument
still
does
not
frack
properly,
the
resistors
have
probably
changed
value.
Return
oscillator
to
the
factory
for
range
switch
replace
ment
and
recalibration.
3-3
Distortion:
I
he
total
harmonic
distortion
will
be
less
than
one-half
of
I
percent
when
the
instrument
is
operating
properly.
If
tubes
are
changed
the
dis
tortion
should
be
measured
if
possible,
because
a
poor
tube
will
increase
the
distortion
without
otherwise
af
fecting
the
operation
of
the
instrument.
Instability
of
the
output
voltage
is
sometimes
caused
by
a
defective
tube
in
the
oscillator
section
Tl
or
T2
or
by
a
defec-.
five
coupling
condenser
which
places
a
positive
voltage
on
the
grid
of
T2.
On
the
following
pages
the
circuit
diagrams
are
shown
for
reference.

Related product manuals