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can see, even low levels produce a significant amount noise, and the level increases
approximately linearly with pulse intensity.
3τos.aff
l*≡T4∣
Figure 6 Time series of the noise created by recharging of the pulse-generating capacitors. Here the TMS
was triggered between pulse intervals. The TMS strength was steadily increased after each interval, from
10% to full intensity, which can be seen by the increasing level of noise.
In order to eliminate this noise the TMS coil has to be electrically isolated from
the capacitor bank while it recharges. To accomplish this we connected two industrial
contactors (Tyco Electronics KILOVAC LEV200 Contactors, www.tycoelectronics com)in
series with the TMS coil (Fig. 7). Contactors function like relays, but have arc
suppression systems to prevent pitting or fusing of their contacts from potentials in
excess of a kilovolt. This is necessary as the TMS system puts out seven kilovolts when
set to maximum intensity. The contactors are controlled by pin 10 of the TMS console.
This pin outputs a high signal when the TMS is armed, closing the contactors and