BC-535 Preliminary, Rev. 060126
39
COMMAND IN
– Also
CMD IN
. Command Input. An external input into the
BC-535
allowing the application of
user defined command voltages to the headstage. Connection is via BNC.
command sensitivity
– Selectable scaling of
CMD IN
input. Attenuation values of
CMD IN
are x0.1, x0.01,
and x0.001.
command voltage
– The voltage applied to the headstage resulting in a desired transmembrane
potential in the system under study.
control blocks
– Organization of controls on the amplifier into functional groups. Blocks are delineated
by titled blue boundaries.
current-voltage relationship
– A measure of the way in which the current varies as a function of the
applied voltage. In an Ohmic device (obeys Ohm’s law), this relationship is linear. An
understanding of the current-voltage relationship of a channel yields information about that
channel’s function.
depolarization
– A biological membrane in which charge separation has resulted in transmembrane
voltage is termed ‘polarized’. Electrically, depolarization refers to any action which tends to
reduce the degree of polarization. Biophysically, a polarized membrane has a resting
transmembrane potential between –40 and –90 mV, relative to the inside of the cell. An action
which tends to increase the polarization (e.g., increase the transmembrane potential to, say, -100
mV) is termed hyperpolarization, while depolarization refers to any action which decreases the
transmembrane potential. (It should be noted that by this definition, a transmembrane potential
of +100 mV is still depolarized.)
digital
– Quantized or discrete. Normally refers to information manipulated by a computer. All
processes within a computer are discrete and are composed of 0’s and 1’s. The universe we
interact with is functionally analog, therefore information we wish to manipulate with a computer
must be digitized prior to use by the computer.
DIN connector
– Deutsche Industrie Norm. A German standard for electronic and industrial products.
DIN connectors can be 3 to 6 pin plugs with the same outer diameter and appearance.
electrode
– One terminal of a voltage source which can either supply or collect current.
electromagnetic
– From physics. An electric current induces a magnetic field and a changing magnetic
field induces an electric current. Therefore, these two entities are related to each other and are
combined into electromagnetism.
electrophysiologist
– A scientist who combines the disciplines of physics, electrical engineering, and
physiology to the study biological systems.
Faraday cage
– A grounded conducting enclosure which shields its interior from external electric fields.
Named after Michael Faraday, who first described the effect in 1875.
gain
– The numerical value of the amplification of a signal by an amplifier. User selectable in the
OUTPUTS
block of the amplifier.
gain telegraph
– A defined voltage dependent on the gain setting appearing at the associated BNC at
the rear of the amplifier. Used to communicate the gain setting to external devices.
Warner
Instruments
A Harvard Apparatus Company .