ISO-STIM 01B User Manual
version 1.8
page 9
3.5. Operation
3.5.1.
Connections – Noise Reduction
The ISO-STIM 01B comes with a power supply with SubD cable, which is connected to the
stimulus isolation device. The corresponding connector at the ISO-STIM 01B is located at the
rear panel.
Note
: A possible source of noise is the chassis of the stimulator. In a noisy environment, it may
act as an antenna picking up 50 Hz or 60 Hz noise respectively, especially when operating with
current stimuli. In this case, the noise is substantially reduced if the chassis is connected to
ground (see also #
11
, Figure 1).
The stimulation electrode is connected to the isolated output (see Figure 1). We recommend to
use a bipolar electrode for stimulating nerve bundles. This will produce only a short stimulation
artifact at the beginning.
Remember
: If unipolar electrodes are used the whole slice will be stimulated resulting in a DC
shift of the whole slice.
3.5.2.
Operation Modes
BIPOLAR:
The isolator is capable to generate biphasic stimuli by switching the stimulus mode switch to
BIPOLAR ON. In this mode, the stimulus that is set by the user will be followed by a second
stimulus with the same amplitude and duration, but with reverse polarity. There is no delay
between first and second part of the stimulus (except IPG is active, see below). For instance, if
the user sets a positive stimulus of +1 V amplitude and 100 µs duration, this stimulus will be
followed immediately by a negative stimulus of –1 V and 100 µs duration.
BIPOLAR with IPG:
In bipolar mode, a delay between the first and the second, inverse stimulus can be inserted, the
interphase gap (IPG, see Figure 4). IPG time is set by (
#16
)
Figure 4: Interphase gap (IPG)
OPERATION IN THE 10 mA (max.) RANGE
According to Ohm’s law, with 10 V voltage 10 mA current can be achieved
only
if the
resistance of the stimulus electrode is not higher than 1 k
. Otherwise, the current will be less.
