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Axon Axopatch-1D Theory And Operation

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January 1997
Axopatch-1D
PATCH CLAMP
THEORY AND OPERATION
Part Number 2500-119 Rev E, Printed in U.S.A.
Copyright 1989, 1991, 1994, 1996, 1997 Axon Instruments, Inc.
No part of this manual may be reproduced, stored in a retrieval system, or transmitted, in any
form or by any means, electronic, mechanical, photocopying, microfilming, recording, or
otherwise, without written permission from Axon Instruments, Inc.
A
-1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC.
XOPATCH

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  • Page 1 THEORY AND OPERATION Part Number 2500-119 Rev E, Printed in U.S.A. Copyright 1989, 1991, 1994, 1996, 1997 Axon Instruments, Inc. No part of this manual may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from Axon Instruments, Inc.
  • Page 3 FRAGILE and an Supply Voltage The Teflon input connector arrow showing which way is up. The Axopatch-1D is set at the factory to should be kept very clean. accept either 115 or 230 V~. The We do not recommend using loose foam...
  • Page 4 MANIERE DIFFERENTE A CELLE En général, la meilleure façon d'emballer SPECIFIEE PAR LE FABRICANT maintenue trés propre. Un nettoyage l'Axopatch-1D est de le mettre dans son AFFECTERA LE NIVEAU DE efficace consiste à vaporiser de carton d'origine. Si celui-ci n'est PROTECTION FOURNIT PAR l'alcool ou á...
  • Page 5 DIESER APPARAT IST NICHT und Sicherheit der Ausrüstung Versand des Axopatch-1D VORGESEHEN, BEI MENSCHLICHEN 1. Netz- und Bei dem Axopatch-1D handelt es sich um VERSUCHEN VERWENDET ZU Erdungsanschlüsse: Das Instrument mit ein solide gebautes Instrument, das beim dem beigefügten IEC Netzkabel an...
  • Page 6 En general, la mejor manera de empacar instrumento ( “C headstage” ) y LAMP PROTECCIÓN PROVISTA POR EL el Axopatch-1D es en la caja original de el de la solución ( “B headstage” ) EQUIPO. fábrica. Si ésta ya no se encuentra...
  • Page 7 Aus (Netz) Apagado (suministro) On (Supply) Allumé (alimentation) An (Netz) Encendido (suministro) Off (Supply) Éteint (alimentation) Aus (Netz) Apagado (suministro) Protective conductor terminal Borne du conducteur de protection Schutzleiterpol Terminal de conductor protector -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 9 RESISTOR/CAPACITOR MODELS OF THEIR ELECTRODES AND CELL MEMBRANES. DISCLAIMER THIS EQUIPMENT IS NOT INTENDED TO BE USED AND SHOULD NOT BE USED IN HUMAN EXPERIMENTATION OR APPLIED TO HUMANS IN ANY WAY. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 11: Table Of Contents

    Holding Potential........................23 Test ........................... 23 seal Ext. Command Sensitivity....................... 24 Speed Test ..........................24 Command Summing........................ 24 Current and Voltage Conventions ....................24 Positive Current........................25 Inward Current ........................25 Outward Current........................25 -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 12 Headstage Gain Adjustment ....................35 Case Ground Connector......................36 Mounting the Headstage......................36 Cleaning........................... 36 Static Precautions ........................36 Optical Pick-up ........................36 Where to Place the CV-4 Boost Box ..................36 -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 13 Leak Subtraction........................46 Auto Output Zero ........................47 Distortion-free AC Coupling....................47 Principle of Operation ......................47 Output Calibration ........................47 Internal ............................ 48 External ........................... 48 Suggested Use ........................48 Pipettes ............................48 -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 14 ß = 0.1 for Large Cells......................55 Limitations..........................55 Ten-Turn Potentiometers ......................56 Trouble Shooting .......................... 56 Zap ..............................56 Suggested Use.......................... 56 SPECIFICATIONS..........................57 SERVICE............................... 63 General............................63 Maintenance..........................67 Adjustment Procedure........................68 -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 15 Page REFERENCES ............................73 WARRANTY ............................75 INDEX..............................81 -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 16: List Of Diagrams

    Assorted #2 .........................A-10 Assorted #3 .........................A-11 RMS Meter .........................A-12 Power Supply ........................A-13 Track Component Location ....................A-14 Track ...........................A-15 Command Potentials ......................A-16 Thumbwheel-to-Voltage Convertor..................A-17 Component Locations ......................A-18 Front and Rear Panel Diagrams ..................A-19 -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 17 FRONT AND REAR PANEL Front and Rear Panels of the Axopatch-1D -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 19: Introduction

    To further assist you in your experiments we have endeavored to write this manual not only as a succinct guide to the operation of the Axopatch-1D but also as a guide to experimental techniques that we have found useful during several years of patch clamping. A modest amount of theory has been included to round out and provide the basis for the practical explanations.

  • Page 21: Features

    The Axopatch-1D works in current-clamp mode as well as the more usual voltage-clamp mode. The feedback resistor may be remotely switched to enable single-channel and whole-cell currents to be recorded in the same cell.
  • Page 22 (voltage clamp) mode is used to control the pipette potential. This is the conventional V-CLAMP method for patch clamping and the primary operational mode for the Axopatch-1D. (current clamp) mode is used to control the pipette current. In this mode the series- I-CLAMP resistance controls act like the bridge balance on a microelectrode amplifier.
  • Page 23 I-CLAMP PATCH-1U Model Cell The model cell is an invaluable aid when learning to use the Axopatch-1D and while setting up or reconfiguring an experiment. The model cell can emulate three experimental conditions. Bath mode is equivalent to touching the electrode to the bathing solution. Cell mode emulates a whole-cell recording configuration.
  • Page 24 Strong emphasis has been placed on quality. Precision ten-turn potentiometers, reliable switches and gold plated connectors are used throughout. Ultralow-drift low-noise operational amplifiers are used in all critical positions and s are socketed for easy maintenance. Detailed operator's and service manuals are provided. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 25: Functional Checkout

    Page 7 FUNCTIONAL CHECKOUT When you receive the Axopatch-1D you should first run a functional checkout to ensure the proper functioning of the instrument. All units are thoroughly tested in the factory before shipping. If you observe any damage caused by shipping or if you encounter problems with the functional checkout, please call the factory.
  • Page 26 Page 8 FUNCTIONAL CHECKOUT All Axopatch-1D controls should be set as follows: Manual Junction Null: About 5 turns from end Auto Junction Null: OFF Series Resistance Comp. % Compensation: OFF Series Resistance Comp. Lag: Full counterclockwise Step Command: 000.0, OFF button depressed Speed Test: OFF Oscillator Freq.: 100 Hz...

  • Page 27: Getting Up And Running - A Tutorial

    GETTING UP AND RUNNING - A TUTORIAL This chapter attempts to ease you into the use and enjoyment of your Axopatch-1D. Please do not be intimidated by the large number of controls. These have been carefully grouped for clarity. Many of them can be switched off and ignored until you become more familiar with the instrument and patch clamping.
  • Page 28 Page 10 TUTORIAL All Axopatch-1D controls should be set as follows: Manual Junction Null: About 5 turns from end Auto Junction Null: OFF Series Resistance Comp. % Compensation: OFF Series Resistance Comp. Lag: Full counterclockwise Step Command: 000.0, OFF button depressed Speed Test: OFF Oscillator Freq.: 100 Hz...
  • Page 29 SCALED OUTPUT For now, use the connector on the front panel. 3. A cable from the output to the COMBINED OSCILLOSCOPE TRIGGER EXT. TRIGGER input of your oscilloscope. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 30 For ß = 1 and ß = 0.1 the meter readings are in nA; otherwise the meter readings are in pA. Using the Pipette Holder holder, supplied with the Axopatch-1D accepts pipettes with an outer diameter of 1.0 to HL-U 1.7 mm.
  • Page 31 Patch position, you should be using around 10 mV on the switch. STEP COMMAND After you have made this measurement, switch off the and return the filter STEP COMMAND -3 dB to 2 kHz. FREQ. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 32 TRIGGER COMBINED OSCILLOSCOPE TRIGGER trigger from the internal oscillator of the Axopatch-1D, or the trigger from your pulse generator, depending on which of them is on. This makes it easy for you to trigger your oscilloscope irrespective of the command source.
  • Page 33 80% compensation means that the 50 mV voltage drop that would be caused by a 10 nA current in a 5 MΩ electrode will only cause a 10 mV error in the clamp potential (i.e., only 20% of the uncompensated error). -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 34 ) can be used with all values of ß, although it is most often used with I-CLAMP ß = 1 or ß = 0.1. You should be aware that voltage recording (current-clamp) in the Axopatch-1D or any other patch clamp is not nearly as fast as voltage recording in a conventional current clamp such as the Axoclamp or Axoprobe.
  • Page 35 Axon Instruments are already designed to record these values. CLAMP Current Convention The current convention used on the Axopatch-1D is that current out of the electrode is positive. Boost Box The inherent bandwidth of a 50 GΩ resistor is only a few tens of Hertz, while for single-channel recording a bandwidth of many kilohertz may be required.

  • Page 37: Reference Guide

    REFERENCE GUIDE Page 19 REFERENCE GUIDE The controls and operation of the Axopatch-1D are described in this chapter. The topics are arranged in alphabetical order. Audio Monitor The audio monitor is a voltage controlled oscillator ( ) that drives a small speaker. The control...

  • Page 38: Non-Use

    Non-use If you are not using the bath headstage for a particular experiment, you should either ground the input of the bath headstage or disconnect the bath headstage from the rear panel of the Axopatch-1D. Capacitance Compensation Pipette Capacitance Compensation...

  • Page 39: Membrane Capacitance Compensation

    Membrane Capacitance Compensation controls are used to charge the membrane SERIES RESISTANCE WHOLE-CELL CAP. capacitance (C A simplified circuit of these controls is: C2 = 5 pF SERIES RESISTANC E 20 VCMND WHOLE-CELL CAP. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 40: Ss = 0.1 For Large Cells

    This procedure leads to unique settings of the controls SERIES RESISTANCE and WHOLE-CELL CAP. corresponding to the electrode and cell being clamped. Next, you would usually set the controls as described in the Series Resistance % COMPENSATION section. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 41: Limitations

    TEST SEAL Only 0.2 mV or 20 mV can be selected and these are gated by the internal oscillator. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 42: Ext. Command Sensitivity

    ß = 0.1/100U headstage for this procedure. Command Summing Commands from all active sources sum linearly. Current and Voltage Conventions The terminology used in this discussion applies to all amplifiers manufactured by Axon Instruments. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 43: Positive Current

    In whole-cell voltage clamping, a positive shift in the command voltage causes a positive shift in and is said to be depolarizing. A negative shift in the command voltage causes a negative shift in V and is said to be hyperpolarizing. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 44: Patch Clamp

    This approach has been rejected by Axon Instruments because of the real danger that if the researcher forgets to move the switch to the preferred position, the data recorded on the computer could be wrongly interpreted.

  • Page 45: Summary

    2. A positive shift in the command potential is: Cell-attached patch hyperpolarizing Inside-out patch hyperpolarizing Outside-out patch depolarizing Whole-cell voltage clamp depolarizing 3. The correspondence between the command potential (V ) and the transmembrane potential CMND ) is: -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 46: Current Clamp

    Whole-cell voltage clamp Vm = Vc Current Clamp In current-clamp mode, the Axopatch-1D can be used similarly to a conventional microelectrode amplifier. The error due to electrode voltage drop during current-passing can be compensated by using the control (analogous to "Bridge Balance" in a conventional SERIES RESISTANCE microelectrode amplifier).

  • Page 47: Series Resistance

    The most convenient way to set the pipette capacitance compensation in voltage-clamp mode, as described in the Capacitance Compensation, Suggested Use section of the REFERENCE GUIDE chapter. Once the controls are optimally set, switch back to current clamp. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 48: Limitations

    REFERENCE GUIDE Limitations Current-clamp in the Axopatch-1D or any other patch-clamp amplifier is not as fast or stable as current-clamp amplifier (i.e., voltage recording) in a conventional current clamp such as the Axoclamp or Axoprobe. This is because of the significant differences in the design of the headstages.

  • Page 49: Grounding And Hum

    4. Try grounding auxiliary equipment from a ground distribution bus. This bus should be con- nected to the Axopatch-1D via the yellow banana (4 mm) socket on the rear panel. This socket is connected to the Axopatch-1D's signal ground (i.e., the outer conductors of all the con- nectors).

  • Page 50: Headstages

    In fact, despite the slow probe output, the voltage clamping of the pipette is very fast. The op amp acts to keep its negative input equal to its positive input and it does this by passing a current (I -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 51: What Is Clamped

    The two gains (ß) available in your particular headstage are marked on the probe cover. Use the switch on the front panel of the Axopatch-1D to select one of these values. All HEADSTAGE GAIN headstages have a higher gain of 100.

  • Page 52: Tuning Cv-4 Headstages

    PATCH-1 headstage CV-4-0.1/100 CV-4-1/100 Precision screwdriver, 2 mm head Prior to adjustment, set " ", " ", and " " % COMPENSATION SERIES RESISTANCE WHOLE CELL CAP fully counter clockwise. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 53: Headstage Gain Adjustment

    -1 mV command should yield -95.0 pA. (Hint: Don't be fanatical about this.) Command voltages: ß = 1 100 mV + and - 10.00 nA ß = 100 + and - 100.0 pA -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 54: Case Ground Connector

    In general, low light levels are not a problem. Where to Place the CV-4 Boost Box boost box should be plugged into the violet jacks on the rear panel of the Axopatch-1D. It is CV-4 not electrically necessary to do this but it is advisable for mechanical and convenience reasons.

  • Page 55: Other Precautions

    REFERENCE GUIDE Page 37 Other Precautions You should switch off the power to the Axopatch-1D before plugging in or removing a headstage. Pipette Holder Features series holder provides for enhanced low-noise mechanically stable microelectrode HL-U recordings with or without suction. Because the new holder provides a universal fit for a very wide...

  • Page 56: Use

    (10 of each size) and one 70 mm length of silicone tubing. Cut into 2 mm lengths, the silicone tubing will yield approximately 30 replacement silicone seals. Additional cone washers, silicone tubing, pins and silver wire can be purchased from Axon Instruments, as well as optional Ag/AgCl pellet assemblies.

  • Page 57: Glass Dimensions

    1 For easy-to-use recipes see Microelectrode Methods for Intracellular Recording and Ionophoresis, by R.D. Purves, London: Academic Press, 1981, p. 51. The Axon Guide. Foster City, CA: Axon Instruments, Inc., 1993, p. 83. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC.
  • Page 58 I trace from jumping into saturation. During mode, I is severely distorted. The effect is very like coupling. The TRACK Axopatch-1D should never be left in mode once data is being recorded. To remind you TRACK that is on, a red glows continuously.

  • Page 59: Implementation

    100 Hz. Select . Optionally, switch TRACK AUDIO MONITOR = I. Approach the membrane and form a seal. The track circuitry should keep the OUTPUT SELECT current trace on screen all of the time. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 60: Main Meter

    Mode The primary operating mode of the Axopatch-1D is voltage-clamp mode. That is, the pipette potential ) is controlled while the pipette current (I) is measured. An alternative operating mode of the Axopatch-1D is current-clamp. In current clamp mode, I is controlled while V is measured.

  • Page 61: Use

    16 ms. model cell can conveniently be used in conjunction with the tutorial at the front of this PATCH-1U manual. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 62: Noise

    The feedback resistors. Even ideal resistors exhibit thermal noise. In addition, real resistors have excess noise. The origins of this excess noise are not well understood, especially for high-value resistors. The Axopatch-1D headstages use thin-film chip resistors which have been empirically chosen for their combination of low noise and tuneability.

  • Page 63: Oscilloscope Triggering

    An external sequencer during recording phases. It is inconvenient to have to re-cable the external trigger input of the oscilloscope each time the timing sources are swapped. The Axopatch-1D has a facility for mixing (by logical 'ing) the trigger outputs of the two timing sources, thereby making re-cabling unnecessary.

  • Page 64: Gain (Α)

    Since LEAK SUBTRACTION both the Capacitance Compensation and Leak Subtraction controls are driven by the command voltage, the passive responses remain eliminated for all polarities and magnitudes of command. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 65: Auto Output Zero

    That is, the signal is only sampled to within 10 mV accuracy. This quantization error is normally too small to be noticed on the oscilloscope screen if the vertical oscilloscope display is set to display the full signal. Output Calibration -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 66: Internal

    Corning #1723 aluminosilicate glass, but it does not require the high heater currents necessary for #1723. It is the most versatile of glasses we have tried since it can be used for low-noise, low-loss patch electrodes and whole-cell electrodes. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 67: Pulling

    It is also important to be sure that no fluid exists in the upper -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 68: Power Supply Glitches

    A gentle stream of gas to dry solution droplets near the top of the pipette is useful. Power Supply Glitches The Axopatch-1D has been designed to minimize the effects of power supply transients (glitches). This is achieved by: taking the incoming power through a radio-frequency interference ( ) filter, and capacitively isolating the transformer primaries and secondaries.

  • Page 69: Changing The Fuse

    Mark the new operating voltage on the identification plate on the rear of the instrument. Changing the Fuse The Axopatch-1D uses a 0.5 A 250 V slow acting 5 x 20 mm fuse on both voltage ranges. Before changing the fuse investigate the reason for its failure. To change the fuse: 1.

  • Page 70: Expected Values

    ), ß = 100, then for various values of R the current SEAL amplitude will be: 1 MΩ, I = 200 pA 10 MΩ, I 20 pA 100 MΩ, I 2 pA -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 71: Series Resistance

    Special circuit designs are used so that the whole-cell compensa- tion is automatically adjusted to follow the reduction in the membrane charging time constant. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 72: Saturation

    Only advance the Lag as far as you need to maintain stability because the more it is used the less compensation there is of high-frequency currents. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 73: Suggested Use

    100 pF. To deal with larger capacitances it is not practical to simply increase C2 inside the headstage because this linearly increases the high-frequency noise. The alternative approach used in the Axopatch-1D is to use a ß = 0.1 headstage. This has a smaller feedback resistor (R2 = 50 MΩ) and no C2 capacitor.

  • Page 74: Ten-Turn Potentiometers

    This clears the oxide off the element and restores noise-free operation. Trouble Shooting It has been our experience at Axon Instruments that the majority of troubles reported to us have been caused by faulty equipment connected to our instruments. If you have a problem, please disconnect all instruments connected to the Axopatch-1D except for the headstage.

  • Page 75: Specifications

    Test signal applied via capacitor direct to input; no holder or electrode. Typical Bandwidth: -3 dB frequency: 20 kHz for ß = 100 (6 kHz with a CV-4B 80 kHz for ß = 1 80 kHz for ß = 0.1 -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 76 These controls are used to charge membrane capacitance in whole-cell voltage clamp. For ß = 0.1, whole-cell capacitance is not operative. In mode Series Resistance I-CLAMP compensates electrode voltage drop. Whole-Cell Capacitance Compensation is not operative. Controls are not operative for ß = 100. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 77 Nulling potential adjusts to maintain zero pipette current. Approximately 100 ms time con- Auto: stant in mode. When mode is selected, value is sampled and held TRACK HOLD indefinitely. Reset button for fast nulling. flashes in , shines continuously in HOLD Track. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 78 0.4 V / increment starting at 0.4 V for 20 Hz, inverted for filter on Bypass. Filter precedes gain amplifier. Leak Subtraction: Internal: Signal proportional to command subtracted from current record. ∞ Range: 10ß MΩ to External: Subtraction proportional to applied voltage, ß pA/mV. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 79 (D) are 1/4, 5/16 or 3/8" (6.3, 7.9 or 9.5 mm). Specify required mounting-rod diameter with order. A removable polycarbonate mounting plate 2.45 x 1.94 x 0.25" (62 x 49 x 6.3 mm) is supplied. Cable length is 10 feet (3 m). -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 80 12 months parts and labor from date of receipt. Service Service is available at the factory. For further information call us. A factory expert will be pleased to answer your technical and ordering inquiries. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 81: Service

    . This feature is not functional in the current model, thus the input to is grounded. U25B The Zap circuit ( ) applies a pulse to for a duration set on the potentiometer. U30B U33B 1.4 V -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 82 To compensate for the voltage drop across the pipette it is necessary to feed a voltage back to the headstage command input ( ) proportional to the pipette current ( provides some high- -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 83 -bit each time a Reset pulse is generated. The stored U65A A/D U66 -bit word is reconverted to analog in . This value is subtracted from the unfiltered input signal in U65B -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 84 The setting of the thumbwheel switch establishes the current output of the multiplying digital-to-ana- log convertor converts the current output into a voltage output. The polarity and maximum output depends on the polarity and amplitude of the reference voltage connected to -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 85: Maintenance

    Routine Maintenance Routine maintenance is not required. The adjustment procedure should be performed after repairs to the main circuit board but not otherwise. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

  • Page 86: Adjustment Procedure

    Using suitable jumper, connect pin 19 to pin 20 on J1 (designated clamp headstage on rear of Axopatch) Mode = V-CLAMP Thumbwheel = 100.0 CONT. Using DVM monitor TP1 (on Track board) Repetitively switch from + to - Trim RT4 for ±5.00 V -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 87 Apply 1 kHz sine wave to Input to RMS Meter input DVM on TP20 Adjust source magnitude for accurate 100 mV RMS on TP20 Trim RT16 for ten times DVM reading Remove external signal -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 88 Connect square-wave source to TP9, 1 kHz, 1 V Scope on TP13 Select ß = 1/0.1, Series Resistance = 100 MΩ Select 100% COMPENSATION Trim RT1 for 200 mV Remove source Switch % COMPENSATION and Capacitance Compensation controls off -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 89 Thumbwheel = 100.0 OSC., 100 Hz Set Series Resistance to read 0 MΩ Set Series Resistance to read 10 MΩ Trim RT11 to null response Select V-CLAMP mode Thumbwheel = 000.0 OFF -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 91 Further Reading Rae, J.L., Levis, R.A. (1984). Patch voltage clamp of lens epithelial cells: Theory and practice. Molec. Physiol. 6, 115-162. Sakmann, B., Neher, E. (1983). Single-Channel Recording. New York: Plenum Press. -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...
  • Page 93 Page 75 WARRANTY We warrant every Axopatch-1D and every headstage to be free from defects in material and workmanship under normal use and service. For 12 months from the date of receipt we will repair or replace without cost to the customer any of these products that are defective and which are returned to our factory properly packaged with transportation charges prepaid.
  • Page 94 Resistors, 43 Triggering, Oscilloscope, 44 External Command, 24 Transistor, 43 Trouble Shooting, 55 Filter Oscillations Voltage Selection, 49 See Output, 44 Series Resistance, 54 Fuse Changing, 50 Oscillator, Internal, 23 Zap, 55 -1D, COPYRIGHT JANUARY 1997, AXON INSTRUMENTS, INC. XOPATCH...

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