.Alembic Instruments Inc

Electronics for Electrophysiology 

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VE-2 Whole-Cell Patch Clamp Amplifier

The only optimized whole-cell patch clamp that fully compensates for series resistance and eliminates series resistance errors (US patent 6,700,427).

• Voltage Clamp the largest, fastest whole-cell currents under physiologic conditions.
• No more oscillations at high compensation settings. It's stable even when over compensated
• Familiar IV converter architecture means super ease-of-use and easy tuning.

Detailed Description
The VE-2 is an optimized whole-cell patch clamp amplifier featuring the Rs compensator™, a unique circuit that brings complete (100%) series resistance compensation to a conventional patch clamp. In contrast, other patch clamps that use standard Rs compensation will oscillate when set above ~90%. Consequently, other amplifiers always have uncompensated series resistance with a voltage error.

With the Rs Compensator™, you can:
1. Voltage clamp Large and Fast ionic current, while maintaining voltage clamp control;
2. Plot accurate IV curves without shifts or distortions due to uncompensated Rs;
3. Maintain stable Rs compensation even as the pipette resistance shifts during an experiment. Notably, other amplifiers will oscillate if the access resistance decreases during an experiment.

For details on how the Rs Compensator works,
click here.

VE-2 Operating Modes
The VE-2 has three operating modes: Voltage clamp, I=0, and Current Clamp.

Voltage Clamp:
The pipette voltage is clamped to a command signal. The command signal is derived by summing the  external command (scaled BNC input), the holding potential (+/- 200mV via calibrated ten turn dial), and the pipette offset control (+/- 200mV calibrated via ten turn dial).

The pipette current is clamped at zero, and the command inputs are disabled. This mode is useful for determining the cell resting potential and for presetting holding commands.

Current Clamp: The pipette current is clamped to a command signal. The command signal is derived by summing the external command (scaled BNC input) and the holding current control (+/- 20 nA). This mode is useful for evoking and recording action potential in excitable cells.

The VE-2 features an optimized, patented headstage design for wideband current clamp mode (20kHz bandwidth in most whole-cell configurations), allowing the VE-2 to record undistorted action potentials in excitable cells.

Series Resistance Compensation
The VE-2 features the unique Rs compensator™ circuit that allows stable 100% Rs compensation and wide bandwith.
You can fully compensate for series resistance using a calibrated ten-turn dial in either low (0-20Meg) or high (0-100Meg) resistance ranges.

Unmatched Capacitance Compensation
The VE-2 features proprietary circuitry to completely compensate pipette capacitance with only one control adjustment, for unequaled ease-of-use.
In contrast, most patch clamps require independent adjustment of four separate controls to achieve similar performance under varying pipette geometries and immersion depths.

Outputs, Controls, and Telegraphs
Im - Scaled pipette current, with selectable scaling factors of 0.05mV/pA through 5mV/pA. Im can be selectively filtered with an internal 4 pole lowpass Bessel filter.

Vm - Pipette voltage X 10

Ext Drive - Digital input/output port through which Mode, Gain, Filter, and Rs compensation range can be set and/or monitored using an external computer. This port also enables the amplifier to be dynamically switched between Current clamp and Voltage clamp under software control.

Telegraph outputs (with optional
Telegraph unit that renders the VE-2 fully compatible with most acquisition software and hardware). Separate analog outputs encode the mode, gain and filter panel switch settings. The telegraph outputs allow popular electrophysiology acquisition software to automatically record these panel switch settings.

LED Panel meter - Meter displays pipette voltage in mV.

Alembic Instruments Inc. 3285 Cavendish Blvd. Suite 570 Montreal, Qc, H4B 2L9 Canada
Fax: 866.240. 2738

Alembic Instruments Beats Series Resistance