Amplifier linear

The signals produced by the strain gauge can be amplified linearly or logarithmically. In the linear mode the displacement of the X-V recorder along the X or pressure axis is inversely proportional to the pore radius as given by equation (10.24)... 

Linear amplifier Linear tail pulse Amplified and shaped linear pulse... 

Transistors are always operated so that amplification is obtained for a signal whose voltage is small on the input side (relative to the bias on the emitter) and small on the output side (relative to the collector voltage). Therefore small-signal theory applies. The designer obviously wants all signals to be amplified linearly, that is, by a common factor this makes the circuit behave more reasonably. 

Figure 3.61. Calibration of the gradient amplifier linearity using the sequence of Fig. 3.59b. Assuming system linearity over the full output range and extrapolating the calibration, the maximum gradient strength provided by this system is 0.51 T m (51 G cm ).

Ramakumar KL, Fiedler R (1999) Calibration procedures for a multia)llector mass spectrometer for cup effi-dency, detector amplifier linearity, and isotope fractionation to evaluate the aouracy in the total evaporation... 

The modulated visual IF signal is processed for distortion corrections and subsequent RF transmission in the following stages (1) power amplifier linearity correction, (2) power amplifier group delay correction,... 

Where space is not a problem, a linear electron multiplier having separate dynodes to collect and amplify the electron current created each time an ion enters its open end can be used. (See Chapter 28 for details on electron multipliers.) For array detection, the individual electron multipliers must be very small, so they can be packed side by side into as small a space as possible. For this reason, the design of an element of an array is significantly different from that of a standard electron multiplier used for point ion collection, even though its method of working is similar. Figure 29.2a shows an electron multiplier (also known as a Channeltron ) that works without using separate dynodes. It can be used to replace a dynode-type multiplier for point ion collection but, because... 

Operational amplifier. A linear, high-gain DC voltage or current amplifier with high input impedance, low output impedance, and the capability of producing a bipolar output from a bipolar input. 

Where stray currents are involved, several measurements have to be taken that are continually changing with time, simultaneously with each other. A double recorder is most suitable for this. Linear recorders with direct indication of the measurements cannot be used for potential measurements because the torque of the mechanism is too small to overcome the friction of the pen on the paper. Amplified recorders or potentiometer recorders are used to record potentials. In amplified recorders, as in amplified voltmeters, the measured signal is converted into a load-independent impressed current and transmitted to the measuring mechanism, which consists of a torque motor with a preamplifier. The amplifier results in an... 

The linear power supply finds a very strong niehe within applieations where its ineffieieney is not important. These inelude wall-powered, ground-base equipment where foreed air eooling is not a problem and also those applieations in whieh the instrument is so sensitive to eleetrieal noise that it requires an eleetrieally quiet power supply—these produets might inelude audio and video amplifiers, RF reeeivers, and so forth. Linear regulators are also popular as loeal, board-level regulators. Here only a few watts are needed by the board, so the few watts of loss ean be aeeommodated by a simple heatsink. If dielee-trie isolation is desired from an ae input power souree it is provided by an ae transformer or bulk power supply. 

These types of linear regulators were eommonly built before the advent of operational amplifiers and they ean save money in eonsumer designs. Some of their drawbaeks inelude drift with temperature and limited load eurrent range. 

The simplest arrangement for a linear accelerator is shown in Fig. 5. Here a single source, either a self-oscillating magnetron or klystron amplifier with appropriate drive stages, feeds power into a single length of accelerator wave-... 

The tube of Figure 2-2 can be operated as an ionization chamber, as a proportional counter, or as a Geiger counter. The tube output differs radically from one case to another. Because of these differences, the electronic circuitry associated with the tube must also be different for each case if the pulses from the tube are to be reliably selected and counted. In particular, the circuitry will have to differ in characteristics such as stability, amount of amplification, and time of response. In all cases, linear amplification (amplifier output always proportional to tube output) is desirable. 

Scintillation counters also have a characteristic plateau. In the scintillation counter the phototube acts as the primary amplifier with a gain as high as 106. A low-gain linear amplifier may be used in conjunction with a scintillation counter, and, again, the range of amplification in the plateau will be about 103 or 104. 

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