WPI EVC 4000-3 MULTICHANNEL VOLTAGE/CURRENT CLAMP WITH 3 EVC3 PREAMPLIFIER

A multi-channel Voltage/Current clamp apparatus for the study of the electrical properties of epithelial tissues, EVC4000 employs the voltage clamp technique to study temporal changes in membrane permeability as a function of membrane voltage or applied chemical agents. This instrument can measure up to four tissue samples simultaneously. Each module, with its companion preamplifier, can operate independently in one of three different modes:Voltage Clamp (VC), Current Clamp (CC) or Open Circuit Potential (PD) measurement. Operation of the EVC4000 can be effected manually from the front panel of the instrument or from computer generated commands applied at the rear panel of the instrument.

DESCRIPTION EVC 4000-3

• Up to 3 channels and a wide range of voltage clamp commands .
• Safe, low-voltage system is easier to adjust and use.
• Superior design of the cartridge electrodes makes 100V current excursion unnecessary.
• A unique feature of the EVC4000 preamplifier is a local circuit that maintains the potential of the V2 electrode invariant at zero potential relative to the system ground.
• Each channel module of EVC4000-3 provides power to its own remote preamplifier EVC3 connected by a flexible cable to the front panel.
• 3 Clamp module with digital panel meter on each control section is a 3½-digit light emitting diode (LED) display. Using the Meter Select switch,membrane voltage in millivolts or trans-membrane current flow in microamperes will be displayed.
• PD, VC, CC: Push buttons, adjacent to indicator lamps, initiate one of three different operating modes; PD (open circuit membrane potential difference), CC (constant current or “current clamp”) or VC (voltage clamp).
• VOLTAGE RECORD: An output connector for display of membrane voltage on a recorder, computer or oscilloscope.
• CURRENT RECORD: An output connector for display of current magnitude and polarity ( 1 millivolt = 1 microampere).
• OVERLOAD: Lamps I1 and I2, when lit, indicate that a limit has been reached in the circuit serving the current electrodes. This may be due to excessive clamp current, a defective electrode or an open circuit in the current electrode pathway. An audible alarm sounds if either lamp is lit.
• EVC4000-3: 3-Channel Voltage Clamp & preamplifier.

Benefits

• Voltage or current clamp up to 3 sample membranes simultaneously
• Use front panel or computer commands to control.
• Hold serosal electrode invariant potential at zero relative to system ground.

Applications
● Monitor membrane permeability as a function of membrane voltage or applied
chemicals.

Voltage or current clamp 3sample membranes
When combined with WPI’s patented EKC and EKV cartridge electrodes,EVC4000 can efficiently voltage or current clamp up to four sample membranes simultaneously using safe moderate voltages on the current wire leads. The superior design of the cartridge electrodes makes 100-volt current excursion unnecessary, so this safe, low-voltage system is easier to adjust and use. Extremely stable and accurate, each module, with its companion preamplifier, can operate independently in one of three different modes:

• Voltage Clamp (VC),
• Current Clamp (CC), or Open Circuit
• Potential (PD) measurement.

Front panel or computer commands to control EVC4000 can be controlled from the front panel of the instrument or from computer generated commands applied at the rear panel of the instrument.

Hold serosal electrode invariant potential at zero
A feature unique to EVC4000 is an electronic potentiostat in the preamplifier box that maintains the serosal electrode invariant potential at zero relative to system ground. The preamplifier apparatus actively maintains one surface of the test membrane close to ground potential under all operating conditions.

EVC4000-3 SPECIFICATIONS

• PREAMPLIFIER

                                     Input Resistance 1012 Ω
                                     Input Leakage Current 100 pA, max.
                                     Maximum Input Voltage ±15 V

• VOLTAGE CLAMP

                                            Panel Display ±200 mV ±0.1 mV
                                            Clamp Voltage / External Input 100 mV/V
                                            Range of Voltage Electrodes ±32 V
                                            Max. Clamp Voltage ±100 mV
                                            Fluid Resistance Compensation 0 to 1000 Ω

• CURRENT CLAMP

                                     Panel Display ±999 µA ±1 µA
                                     Maximum Clamp Current ±1 mA
                                     Current Clamp Output 1 µA / mV

• DISPLAY RESOLUTION  -Voltage 0.1 mV

                                                Current 1 µA