High-impedance value

For the fitness function a normalization of the difference between simulated and measured data is used in to get a uniform distribution of the deviations at low and high impedance values. With the weighting factor H N - 1) the results get more independence on the exact number of frequencies. 

One specification often stated is the pH meter input impedance. Its value is typically 10 ohms. This high impedance value is required to handle the high resistance of the glass bulb. The glass bulb resistance value typically varies with electrode configuration and type of glass, but is usually between 10 and 10 ohms. The... 

A signal can only be assigned a high impedance value under a controlled condition such as inside an If or a Case statement. 

An unknown, don t care or high impedance value used as an operand in an (7=0 operation will always return FALSE (TRUE). 

A high impedance value can be assigned within or used in the conditional logic of a Case or If statement. 

Comparable fuels. In order to promote the recycling of materials with high fuel values, certain materials that are burned as fuels are excluded from the definition of solid waste, provided that they meet certain specifications (i.e., are of a certain degree of purity). This is to ensure that the material does not exceed certain levels of toxic constituents and physical properties that might impede burning. Materials that meet this specification are considered comparable to pure or virgin fuels. 

For each specimen an average over 122 cycles were taken, but because of the high impedances present, a perturbing voltage of 115 mV was used. This is somewhat higher than the theoretical value arrived at by Meszaros but necessary because of the low level of harmonic signal from the specimens. The visual appearance of each electrode was noted for comparison with the electrochemical data. 

If a resistance is placed in the feedback loop (Fig. 6.6b), the bias current ib will also create a difference between Ej and E0 by an amount ibRr. Even very inexpensive (< 1) OAs can have bias currents of less than 10 9 A, which means that the value of Rr will have to exceed 1 MO to create a 1-mV error. Amplifiers with bias currents of less than 0.1 pA (10 13 A) are available. Using the same criterion, Rr may then reach 1000 MQ, a value well beyond any resistance commonly encountered in dynamic electroanalytical techniques. Such amplifiers are, however, eminently useful for constructing pH meters and pH stats and measuring potentials in electrophysiology, where very small high-impedance electrodes are often used. 

FIGURE 6.9 Typical wiring of a photomultiplier. Each of the dynodes, beginning in the photocathode, is linked stepwise by resistors RD of the same value. The photocurrent is read as the voltage drop across the load resistor R with high impedance filter (Rf, Cp) and oscilloscope or transient digitizer (detector). 

For bulk dielectrics, a dielectric resonator can be formed by a cylindrically shaped piece of dielectric material. Dielectric thin films are more difficult to investigate, in particular when the loss tangent is very small. Planar resonator techniques as well as specially designed dielectric resonators can be used to examine their properties. For high-temperature superconductors both dielectric resonators and planar resonators represent an ideal tool to examine their surface impedance values. 

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