CA-1B High Performance Oocyte Clamp

The CA-1B is the Worlds quietest and fastest Oocyte Clamp,

and it does both Cut Open Vaseline Gap and classical Two Electrode


Click HERE for full size front panel 


 Features ...

  • Cm Compensation - with three time constants. Cm transients can be tuned out in the BATH before the current to voltage (I/V) converter, eliminating any chance for an amplifier stage to become saturated
  • Leakage Resistance Compensation - Also done in the BATH before the I/V converter
  • Series Resistance Compensation - Ten-turn calibrated dial
  • Three Active Headstages (Vi, V1, V2) - Each with front panel controls for Offset, Capacity Compensation and Z Test that reads both on the Digital Meter and the 10V output BNC's
  • Fourth Headstage (Bath/Guard) - Contains Voltage Clamp circuitry for Cut Open Guard compartment, output pin for Cm and Leakage Compensation, and also the Im current to voltage converter. There are eight front panel selectable Im gain ranges for the Bath/Guard Headstage [GAIN (a)], giving the actual current to voltage converter in the headstage ranges from 0.05mV/nA to 100mV/nA
  • Processed Output Section: [GAIN (b)] - Adds additional gains of 1, 2, 5, 10, 20 or 50 to the Im signal
  • Offset - Ten-turn dial allowing for a + 2 volt DC offset to be added to the Im signal
  • Filter - Twelve-position four pole bessel low-pass filtering of Im signal
  • Im Blanking - Two independent (CMOS 5 volt logic) back panel BNC inputs that blank the Im signal at the Bath/Guard Headstage
  • Scope Trigger In/Out - Input Trigger signal from computer/stimulator is added to the internal Z Test and Clamp Test and sent to one Trigger output BNC
  • Telegraph Outputs - Separate back panel telegraph output BNC's for Gain (a), Gain (b) and Filter settings

 Modes of Operation:
TEV Mode

Conventional Two Electrode Clamp with 145 volt compliance and three time constant Cm compensation. These capabilities are combined with a very high performance bath clamp that enables you to clamp twice as fast as any two electrode clamp available to date.
CUT-OPEN Mode (Mainframe)

A new unique Cut-open Oocyte Vaseline-gap method that is both very quiet, and is also fifty times faster (20 to 100 µs to change the membrane capacitance) than any oocyte clamp ever built. With this mode of operation, it is now also possible to control the intracellular milieu by internal perfusion of the oocyte. Now, stable recording lasting for several hours is possible. These properties allow the resolution of the time course of fast ionic and gating charge currents. Current noise is only about 1nA RMS at 3kHz bandwidth: a significant improvement over conventional two electrode oocyte clamps.

CUT-OPEN Mode (Headstage)

In this mode the Mainframe Clamp Amplifier is replaced by the Clamp Amplifier in the V1 Headstage. This eliminates much of the feedback path from V1 electrode (Voltage Monitoring) to I(Current Injecting) output. It improves speed and makes the CUT-OPEN operation even lower in noise (by a factor of 2 or 3 times!!)

The CA-1B is designed to be easy to use, yet provide excellent performance for the most demanding applications. The CA-1 was designed by Dr. Enrico Stefani in collaboration with Dr. Francisco Bezanilla, both with the UCLA School of Medicine. To view experimental data obtained by them using a CA-1, click here. In addition to the TEV mode, there have been many enhancements to Series Resistance compensation since publication of this technique. And now there is also a Processed Output Section.

Click here to view more illustrations 

Temperature Control

The Cut-Open Chambers can also be temperature-controlled by either of the two Dagan Temperature Controllers (TC-10 or HCC-100A) along with the specially designed HE-104C Thermal Stage.

  • HE-104C
  • Thermal Stage for temperature controlled applications with recessed area for chamber . Is interchangeable with any Dagan Temperature Controller. See Temperature Control data sheet for more information.

Cut Open Chamber Configurations and Accessories

  • CC-1-P-LB 
  • Basic Main Chamber . P for polycabonate  Does not include boat set
  • HE-104C or HE-204C
  • Temperature control stage to be used with Dagan TC-10 or HCC-100 heating/cooling controller.
  • MS-104
  • Mounting Stage for non-temperature controlled applications. 3.6x3.8" plastic plate with six 8-32 threaded mounting holes and a recessed area for chamber.
  • PL-6
  • A plastic block holding six Ag/AgCl pellets with six-inch wires and mating pins to the Bath/Guard Headstage. The plastic block has six wells for glass agar bridges that would then connect to the various chambers on the CC-1

Chamber Availability

We are not currently carrying most of the CA-1B chambers that we have historically carried. We recommend that

customers have their own chambers machined. Please see this JOVE article for descriptions and dimensions.


To view an application example showing the improved results obtained when a temperature controller is used in conjunction with a voltage clamp experiment, click here.


For a list of references using the CA-1B as well as a link to excellent techniques publications, click here.

Download the Manual (PDF)


'Clampator One' High Performance Oocyte Clamp (115 or 230 V AC) with all headstages (no chamber)



Same as above, but without TEV mode


CA-1B/HS Complete Set of spare Headstages Only
(Vi, V1/i, V2, BathGuard I/V)
CA-1B/Vi spare Vi Headstage $940.00
CA-1B/ I/V spare Bath Guard I/V Headstage $1,460.00


spare V1 or V2 headstage


CC-1-P-LB Polycarbonate plastic Chamber     $520.00


6 Ag/AgCl pellet assemblies in block with 6 wells to couple to the above cut-open chambers (Temporarily Unavailable)



Replacement Ag/AgCl pellet for PL-6



Chamber Mounting Stage for non-temperature controlled applications



Generic rectanular Chamber Thermal Stage for temperature controlled applications



Exact fit round Chamber Thermal Stage for temperature controlled applications


CA-MOD Spare model cell for CA-1 TEV and Cut Open modes $180.00

 Other Two Electrode Clamps:

Warning: This equipment is not intended for use in human applications or human experimentation.

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Dagan Corporation   Email:   3/14