Single Electrode Clamp Amplifier

SEC amplifiers (npi electronic) are versatile intracellular recording systems. 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.

For more information on the SEC amplifiers please visit npi electronic website

Single Electrode Clamp Amplifier

SEC amplifiers (npi electronic 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-05LX

A high speed precision Time-Sharing Single Electrode Voltage/Current Clamp amplifier. The system has digitally controlled output gain and filters.

SEC-10LX

 

A high speed precision Time-Sharing Single Electrode Voltage/Current Clamp amplifier with acurrent range of 150nA/100MOhm.

The above systems are standard versions. All amplifiers are equipped with a standard headstage with a current calibration of 150nA/100MOhm.

Features

Versatility
Use with sharp microelectrodes and suction pipettes
SEC Systems allow all kinds of intracellular investigations - from recordings with sharp electrodes to experiments with suction pipettes.

Standard Modes of Operation
VC, CC, Bridge, Electrode resistance test
All systems are equipped with an automatic electrode resistance test mode, bridge mode and switched mode current- and voltage clamp.

VCcCC Mode
Voltage Clamp controlled Current Clamp
All SEC systems can be equipped with VCcCC mode to allow current clamp recordings at defined holding potentials (Ref.: Sutor et al. (2003), Pflügers Arch., 446, 133-141)

DHC Mode
Dynamic Hybrid Clamp
All SEC systems can be equipped with DHC mode for recording conductances after action potentials (Ref.: Dietrich et al. (2002), J. Neurosci Meth., 116, 55-63)

Microelectrode Compensation
Complete supression of series resistance
All SEC systems use an improved electrode and capacitance compensation circuit. This makes it possible to inject current pulses in the micro-second range with a complete decay of the injection artifact before potential measurement. Therefore, recordings are possible with NO detectable series resistance.

Switching Frequency
20KHz or more with high impedance microelectrodes
SEC systems are the only ones permitting the routine use of high switching frequencies (tens of kHz) in recordings with high resistance microelectrodes. Fast signals, such as action potentials or sodium currents are recorded accurately; even very small cells can be voltage clamped.

Voltage Clamp Performance
Settling Time less than 1ms with a Clamp Error of less than 1%
A powerful proportional-integral (PI) voltage clamp controller gives very fast responses to command steps while preserving a very critical control of membrane potential.

Stability
Protection of preparation from damage
An automatic oscillation shut-off unit helps to protect the preparation from harmful oscillations, while a tunable current limiting circuit prevents the electrode from overload and suppresses stimulus artifacts.

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.

SPEED of RESPONSE (VC Mode):
1 % settling time: <80 µs for 10 mV step and <800 µs for 50 mV step applied to cell model (Re = 100 MOhm, Rm= 50 MOhm, Cm = 470 pF, duty cycle = 25%, switching frequency = 30 kHz, standard headstage); <400 µs with 50% duty cycle.

POWER REQUIREMENTS:
115/230 V AC, 60 W (0.630/0.315 A fuse).

DIMENSIONS:
19" rackmount cabinet, 19" (483 mm) wide, 14" (355 mm) deep, 5.25"(132.5 mm) high, weight 11kg.

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All SEC amplifiers are delivered with standard headstage, cable set and connectors for electrode connection and ground and a user manual. Standard output voltage is ±15 V. High voltage SEC amplifiers (±150 V) are available on request.

Below are options and additional accessories (at additional costs). Customized configurations are possible, please contact us.

• SEC-05LX: Standard SEC-05 system
• SEC-05LX-BF: System with four-pole Besel filters.
• SEC-05LX-CW: SEC-05LX with INFA 08, amplifier control from Cellworks software.
• SEC-XXH: SEC-05LX and SEC-10LX systems with high voltage.
• SEC-SLOW: SEC-05LX and SEC-10LCX system with VC