Induced voltage

While the conventional Eddy current read out uses induced voltage and voltage amplification, the SQUID read out operates the probe as a magnetic flux transformer. This demands to minimize the resistivity of the pick up loop. 

The quantity of interest is the precession of the components perpendicular to B0 that are measured in the experiment by induced voltage in the coil, which is subsequently amplified and demodulated. We can write them either as individual components Mx, M, or by a vector M+, which combines both of them. In the static field, the precession about B0 occurs with the Larmor frequency w0 = /B0. If we neglect those processes which dampen the amplitude of the rotating transverse magnetization as precession proceeds, this already describes the frequency that we pick up with our receiver coil, and it is the third and perhaps the most important of our three fundamental equations of NMR ... 

Lightning Direct strike Hot spot Induced voltage... 

The technique described above measures only light-induced potential changes from a whole population of organisms. Therefore, it had to be verified that these changes are based on a light-induced voltage gradient between the two ends of the... 

Note One inch of trace switching, say, 1A of instantaneous current in a transition time of 30ns, gives a spike of 0.7V. For 3A, and two inches of trace, the induced voltage tries to be 4V ... 

For practical use of pyroelectric elements as infrared sensors and so forth, the induced voltage V is an important quantity. From the relations concerning surface charge. 

The signal-to-noise ratio of a signal correlates to the ratio of induced voltage to noise voltage [1, 20]. It can be described as... 

Paul DL, Ebihara L, Takemoto LJ, Swenson KI, Goodenough DA Connexin46, a novel lens gap-junction protein, induces voltage gated currents in non-junctional plasma membrane of xenopus oocytes. J Cell Biol 1991 115 1077-1089. 

An original technique was developed by Konishi et al. (1969) and extended later on by Narita et al. (1980). This method is known as the small-angle magnetisation rotation (SAMR) method a static bias field H and a tensile stress (o) are applied in the direction of the film a small-amplitude ac driven field H = W max sin(wf) is applied perpendicular to H. It is this ac magnetic field that induces a magnetisation rotation, which can be detected as an induced voltage in a sensor coil wound around the film axis. This response is measured as a function of the applied stress, i.e. of the strain-induced anisotropy. An experimental SAMR set-up is illustrated in fig. 5. The sensitivity of this method was 2 x 10-7 (Narita et al. 1980) and even much higher, namely 10-9 (Hernando et al. 1983). 

When the induced voltage Fopen is not completely in phase with the applied strain, or the induced current is not completely in phase with the applied strain rate (piezoelectric relaxation), the e-constant becomes a complex quantity as follows ... 

Clearly, such interference can be reduced by increasing the distance between the source and the measurement circuit—mutual inductance and capacitance both being inversely proportional to the distance. Inductive coupling can also be much reduced by the use of twisted pair cable (Fig. 6.65). If adjacent loops in the circuit have the same area (e.g. loops 1 and 2) and are coupled with the same magnetic field, then the induced voltages between points A and B and between B and C will cancel each other out, and this will be repeated along the whole section of twisted pairs. 

---