Minolta XE - B. Meter Circuit

The
movement
of
the
shutter
mech.
block
will
turn
on
S,
(trigger
switch)
in
connection
with
the
run
of
the
first
curtain,
and
C2
will
start
charging
via
the
extension
circuit.
On
this
occasion,
the
current
will
flow
through
the
plus
electrode,
Cz,
Tr
for
extension,
Sa,
S’,
and
the
minus
electrode.
The
arithmetically
compressed
voltage
against
the
brightness
of
theobject,
which
was
charged
to
C;,
will
be
converted
in
the
manner
of
geometrical
progre-
ssion.
No.
10
and
No.
6
terminals
of
the
IC
constitute
the
differential
amplifying
circuit
(first
switching
circuit)
in
the
IC.
No.
6
terminal
(trigger
level)
will
be
usually
stabilized
at
about
1.6V
for
the
manual
operation
and
at
about
2.5V
for
the
automatic
operation.
When
S,
is
turned
on,
the
voltage
of
No.
10
terminal
will
decline
because
C2
is
charged
with
the
3V
of
the
power
source
and
will
reach
the
same
value
as
the
trigger
level
of
No.
6
ter-
minal.
Then
the
differential
amplifying
circuit
will
turn
reversely.
With
the
reverse
turn
of
the
first
switching
circuit,
the
delay
circuit
(C3)
will
be
charged
via
Riz.
When
the
charged
voltage
becomes
a
half
of
the
voltage
of
the
power
source,
the
second
switching
circuit
will
turn
reversely.
Then
the
current
of
the
magnet
connected
to
No.
13
terminal
will
be
blocked,
and
the
second
curtain
will
run.
For
the
manual
release
of
the
shutter,
the
Rt
tip
resistance
will
arise
from
the
extension
circuit
by
operating
the
A-M
select
switch,
and
the
CR
time
set
circuit
will
be
made
up
of
Cz
and
Rr.
However,
the
circuit
operation
will
be
the
same
as
that
for
the
automatic
rele-
ase
of
the
shutter.
B. Meter Circuit
The
meter
circuit
is
designed
to
amplify
the
output
of
the
addition
circuit
and
to
operate
the meter.
It
is contained
in the
IC
for the
light
measurement
and
the memory
circuits.
Its
output
is the memory
voltage
of No.
6 terminal
and
its
imput
is
the voltage
of
No.
11
terminal.
The swinging
volume
of
the ammeter
with
an internal
resistance
of 1.2K
varies
depending
on the
combination
of IC,
CdS,
etc.,
but
will be adjusted
by R2.
Table-2
léas
:
Ss
7—o z
Baw C: Auto Manual
4a
a
10
Ic
Te
(Collector 2a
current)
4
S.
Si
0.718 0.736 0.754 (0.772
18m 7 bd
Vee (Ci Charge voltage)
Cy