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SEC
series systems are versatile intracellular recording systems. SEC
systems are the fastest and most accurate single-electrode current
- and voltage - clamp systems available.
These amplifiers are suitable for recordings with high resistance
microelectrodes, for tight-seal perforated patch, or whole-cell
recording techniques. They also allow intracellular recordings
during in vivo voltammetry experiments. Currently, SEC amplifiers
are used in vertebrate (rat, mouse, cat, fish etc.) and
invertebrate (leech, crab, snail, insect etc.) neurons, muscle
cells, other excitable tissue and plant cells.
A significant improvement over other time-sharing amplifiers is
that the SEC systems fully compensate the recording microelectrode. This
allows single electrode recordings with the same accuracy and
speed of response as with the standard two electrode voltage clamp
approach.
All systems include four (optionally six) modes of operation,
many automatic functions,
protection circuits, versatile I/O signal conditioning units, and
digitally controlled operation. All of these features make these
amplifiers the ideal research instruments for all
electrophysiological investigations using intracellular
microelectrodes or suction electrodes (patch pipettes). SEC
systems are also available as modules for the EPMS-07 system. The
combination of two or more SEC modules results in a convenient
instrument for recording in coupled cells.
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MODES
of OPERATION:
Re: Electrode Resistance Test; BR: Bride Mode (continuous); CC:
Current Clamp mode; VC Voltage Clamp mode (discontinuous); Mode
selector: rotary switch with four positions (SEC-05LX), or push
buttons (SEC-10LX), LED indicators; remote selection by TTL inputs.
HEADSTAGES:
Standard headstage (SH) / Whole cell Headstages (SEC-HSP):
Operation voltage ±15 V; size: 100x40x25mm, headstage enclosure
is connected to ground; electrode connector: gold plated SUBCLIC (SH);
BNC connector (SEC-HSP), both with driven shield. Driven shield
output:2.3 mm connector, range ±15 V, impedance 250 Ohm, ground:
2.3 mm connector or headstage enclosure. Input resistance:
>10E+13 Ohm (internally trimmable). Current range (continuous
mode): 150 nA into 100 MOhms (SH); 15 nA into 100 MOhms (SEC-HSP),
other calibrations are possible. CC control: Coarse control for
input capacitance compensation. Holding bar (SH): diameter 8 mm,
length 10 cm. Mounting plate (SEC-SHP headstage) 60x50 mm with
four 6 mm holes.
Differential input headstage (SEC-HSD):
Electrode connectors: two SUBCLIC connectors with driven shield;
Input resistance > 10E+13 Ohms; CMR >90 db; other parameters
same as SH headstage.
High voltage headstage (SEC 10H system):
Operating voltage range: ±150 V; size: 100x50x30 mm with heat
sink 100x50x20, grounded enclosure; connectors same as SH
headstage; CC control: trim potentiometer, 15 turns.
Electrode Parameter Controls:
Leakage current: adjustable to zero with ten-turn control; offset:
ten-turn control, ±400 mV; capacity compensation; range 0-30 pF;
coarse control on headstage, adapts compensation circuit to
electrode parameters; fine control: ten-turn potentiometer.
BANDWIDTH and SPEED OF RESPONSE:
Full power bandwidth (Re=0): >100 kHz; rise time (10-90%, Re =
100 MOhm) <30 µs; rise time (10-90%, Re = 5 MOhm) <8 µs.
Electrode artifact decay (switched modes, 10 nA signal) < 1 µs
(Re = 5 MOhm); <1.5 µs (Re = 100 MOhm) CAP. COMPENSATION tuned
with no overshoot.
ELECTRODE RESISTANCE TEST:
10 mV/MOhm, obtained by application of square current pulses ±1
nA, display XXX MOhm.
CELL PENETRATION:
Overcompensation of capacity compensation, timer controlled, with
remote switch connected via BNC connector (all systems).
Application of DC pulses, variable frequency and amplitude, timer
controlled, with remote switch connected via BNC connector (SEC-10
systems). Application of maximum continuous DC current, BUZZ, with
toggle switch or remote switch connected via BNC connector
(optional SEC-05 systems).
OSCILLATION SHUT-OFF:
Turns off current injection and capacity compensation, function
indicated by red/green LED, disabled / off / reset switch,
threshold set with linear control (0- 1200 mV).
SWITCHED
MODES PARAMETERS:
Switching frequency: linear control, 1.5-50 kHz; display: XX.XX
kHz. Duty cycles: 1/2, 1/4, 1/8, selected by toggle switch.
CURRENT RANGE vs. DUTY CYCLE:
1/8 - 15 nA; 1/4 - 30nA, 1/2 - 60 nA (standard 15V headstage)
1/8 - 1.5 nA; 1/4 - 3 nA, 1/2 - 6 nA (low noise headstage)
1/8 - 150 nA; 1/4 - 300 nA, 1/2 - 600 nA (high voltage headstage).
SWITCHED MODE OUTPUTS:
Electrode potential: max. ±15 V, output impedance 250 Ohm.
Switching frequency: TTL (0.5 V), output impedance 250 Ohm.
CURRENT OUTPUT:
Sensitivity: 0.1...10 V/nA in 1-2-5 steps, with lowpass Bessel
filter, output impedance 250 Ohm; sensitivity monitor: 1...7 V,
1V/switch position, output impedance 250 Ohm; current display:
X.XX nA.
POTENTIAL OUPUT:
Sensitivity x10 mV, with lowpass Bessel filter, output impedance
250 Ohm; potential display: XXX mV.
AUDIO MONITOR:
Pitch correlated with potential signal.
OUTPUT FILTERS:
SEC-05: two-pole (standard version) or four-pole lowpass bessel
filters (SEC-05LX-BF) with 16 corner frequencies, 20 Hz - 20 kHz.
Frequency monitor: -8..+7 V, 1 V/switch position, output impedance
250 Ohm.
SEC-10: four-pole lowpass Bessel filters tunable in three ranges
0.3 - 20 kHz, output impedance 250 Ohm.
CURRENT CLAMP:
Inputs: 1 nA/V, 0.1 nA/V with ON/OFF switches, input resistance
>100 kOhm.
HOLD: X.XX nA ten-turn digital control with -/0/+ switch, max. 10
nA.
Gated input (SEC-10 systems only): X.XX nA with +/0/- switch, TTL
input (HI >2.5 V, input resistance 10 kOhm).
BRIDGE balance: XXX MOhm with ten-turn digital control.
Noise (BRIDGE MODE): 400µV pp / pA pp with 100 MOhm resistance ad
10 kHz bandwidth (internal four-pole Bessel filters).
VOLTAGE CLAMP:
Inputs: :10 mV/:40 mV, input resistance >100 kOhm.
HOLD: XXX mV, ten-turn digital control with +/0/- switch, max.
1000 mV.
RISE TIME LIMIT: 0-2 ms.
GAIN: 100 nA/V - 10 µA/V ten-turn linear control.
Noise (filters set to 10 kHz, other settings see below).
Potential output: <400 µV pp, current output: <400 pA pp
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