User
Guide
for
Axoclamp
900A
Clear
The
Clear
buttons,
Clear+
and
Clear–,
are
located
in
the
I
‐
Clamp
tabs.
In
I
‐
Clamp
mode
only,
the
Clear+
and
Clear–
commands
drive
large
positive
and
negative
current
steps,
respectively,
down
the
micropipette.
Clear+
delivers
a
depolarizing
current
(one
that
causes
a
positive
shift
in
the
membrane
voltage),
while
Clear–
delivers
a
hyperpolarizing
current
(one
that
causes
a
negative
shift
in
the
membrane
voltage).
Clear
is
used
for
two
purposes:
Clearing
blocked
microelectrodes.
If
the
microelectrode
resistance
in
the
bath
seems
much
higher
than
it
should
be,
the
electrode
can
often
be
cleared
by
rapidly
toggling
the
Clear
switch
from
plus
to
minus.
Because
of
the
large
current
passed
this
should
only
be
done
extracellularly.
Penetrating
cells.
Sometimes
microelectrode
tips
press
against
the
cell
membrane
but
fail
to
penetrate.
A
quick
press
on
the
Clear
buttons
will
often
force
the
electrode
to
penetrate.
Whether
to
use
a
hyperpolarizing
or
depolarizing
current
depends
on
the
preparation
and
must
be
determined
by
trial
and
error.
Like
Buzz,
the
mechanism
for
impalement
is
unknown.
Clear
generates
a
Sync
Output.
The
meters
in
Axoclamp
Commander
are
disabled
for
approximately
1
second
after
a
Clear
command
to
avoid
overloading
the
meter
inputs.
Configure
SoftPanel
The
Axoclamp
SoftPanel
is
an
optional
hardware
extension
that
gives
you
control
of
the
Axoclamp
900A
from
a
dials
and
buttons
interface,
rather
than
with
computer
keyboard
and
mouse.
Attached
to
your
computer’s
serial
or
USB
port,
it
has
8
knobs
and
8
buttons
configurable
to
control
your
choice
of
Axoclamp
900A
Commander
functions
(or
you
can
use
default
settings).
120
