The Model 2400 is a low noise, full featured intracellular/extracellular amplifier designed for voltage clamping using patch electrodes on single channels or whole cells. Its unique design allows fast intracellular current clamp measurements with sharp electrodes. Advanced circuit design techniques using field programmable gate arrays eliminated noisy microprocessors.
Amplifier current gain is extremely flexible as it can accept any of four resistive feedback probes. Each probe has two feedback resistors selected from the following values: 10MΩ, 50MΩ, 100MΩ, 1GΩ, 5GΩ, and 10GΩ. The wide range of feedback resistors means currents can be recorded with outputs of 1mV/nA to 10mV/fA. The standard probe sent with each unit is the 100MΩ / 10GΩ version, but other values can be selected.
Features:
- Full Function Patch Clamp Amplifier for both whole cells and patches
- True Current Clamp is 100% stable with bandwidth of 200kHz.
- Switchable Dual Resistive Feedback Headstage
- Capacity, series resistance, and whole cell compensation
- 4-pole Low-Pass Bessel Filters
- Internally generated test signals
- Telegraph outputs for all major front panel controls
- Independent hold, offset, and tracking circuitry
- Displays command potentials, cell currents,and voltages
Headstage for Model 2400
The probe is both a current to voltage converter and a voltage follower. The current to voltage converter used in voltage clamping has one of two high value resistors used for amplifying membrane currents. Below is a table of the different probes you can purchase from A-M Systems, Inc. and their feedback resistors.
The probe has three connections, the input BNC, a ground jack, and a guard jack.
The input BNC will hold any BNC style electrode holder, and is where any input signal should be connected. The center conductor is connected through a current limiting resistor to a field effect transistor amplifier. Other than the current limiting resistor there is no other protection to the probe so care must be taken to avoid electrostatic discharges. The outer conductor of the BNC is connected to a guard circuit. The guard is a buffered version of the input voltage, so care must be taken not to ground the outer conductor of the BNC.