56 • Reference Section
MultiClamp 700A Theory and Operation, Copyright 2000, 2001 Axon Instruments, Inc.
Audio Monitor
• Used for audio monitoring of an electrical signal.
• The Audio control panel is accessed via the toolbar button
.
The Audio Monitor provides auditory feedback for a user-selectable signal (Membrane
Current or Potential on Channel 1 or 2). This is sometimes useful while attempting to
seal onto or impale a cell, since it obviates the need to look at an oscilloscope while
manipulating the electrode.
One of two Audio Modes can be selected.
• Direct Signal Monitoring. The selected signal is relayed directly to the output
speaker. This mode is especially useful for monitoring spikes, which are heard as
audible clicks.
• Voltage Controlled Oscillator (VCO). The voltage of the signal determines the
frequency of a sine wave which is then directed to the output speaker. This is
useful if the signal of interest is a DC signal, e.g. the membrane potential. The
default setting for the VCO is 2200 Hz at 0 V ranging to 300 Hz at -100 mV.