Faraday shield

Figure 11-7 Using the Auxiliary Primary-side Winding to Act like a Faraday Shield...

For the experiments described here a home-built NMR scanner is used, which incorporates an iron-cored electromagnet operating at a field of 0.78 T. In order to perform quantitative measurements a Faraday shield was placed... 

In another report, the electrodes were placed in ultrasonically ablated wells so that they were very close (0.2 mm) to the channel. In addition, a faraday shield was placed between the two electrodes to avoid direct coupling between them. A voltage of several hundred volts was used to achieve low detection limits [773]. 

Tip We don t need to draw any current at all from this Faraday winding to make it work. So it need not even be required by our circuitry (for an auxiliary rail). In that case, we could just wrap a few turns of thin wire (spread out evenly), with one end of it connected to primary ground, and the other end via a small 22 pF capacitor to primary ground. This technique certainly saves production costs associated with the making and placing of a formal Faraday shield — not to mention the improvement in efficiency due to the reduced leakage inductance (as compared to what a formal Faraday shield may lead to). In that sense, this informal Faraday shield is a very useful idea, certainly worth trying out. 

M KCl solution placed in another chamber, a sb spanning over the two chambers. For a two-electrode system as is usually used in the measurement, the newly cut tip of the metallic wire, coated with absorbed lipids, acts as the WE. The current through the s-BLM is measured in the auxiliary electrode during the CV. The setup is housed in a Faraday cage to minimize interference by external noise and electrical transients. In spite of shielding, external noise may still be picked up by the switch box therefore, for the critical measurements the switch box should be incorporated within the same Faraday shield as the cell. All cables used are shielded and the shields are grounded. 

Use of a Faraday shield cage may help to prevent the electromagnetic field from inducing noise currents. 

F FARADAY SHIELD DESCENDING CABLE (connected to the water tube stirrups and to any other iron object). 

Illustration of a microchip incorporating CE separation and contactless conductivity detection, (a) Schematic representation of the microchip including a microchip holder, b electrode plate, c microchip, d screws and clip and e Faraday shield, (b) Anti-parallel detection electrode configuration including f detection electrodes, g basis laminate and h electrode extensions used to connect the signal from the function generator and to the detector circuitry [8]... 

If EKG s are recorded in a Faraday-shielded room using shielded lead wires, records as shown in Figure 10.1c,d can be obtained. Note the absence of 60-Hz interference. In Figure 10. Id, leads I and III exhibit thickening, but this results from muscle tremor signals. The source is the left arm, since this limb is common to both leads. Apparently the strap which anchored the left wrist electrode was too tight, and some EMG signals were produced. 

Figure 10.1. Reproduction of electrocardiographic records (a) Lead II record from canine with 60-Hz trace thickening in record, (b) Record produced by two opposing stainless-steel-mesh disc electrodes sutured to the ventricles of a canine heart (1 mV/cm vertical deflection time base 0.2sec/cm). (c) Lead II tracing from young adult human male recorded in a Faraday-shielded room, (d) Leads I-III tracings from young adult human male using shielded leads and recorded in a shielded room. Note EMG signals in leads I and III. Chart speed is 20 mm/sec.

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