Voltage amplifier

Rectifiers working according to the control diagram in Fig. 8-6 are used for anodic corrosion protection in passivatable systems that go spontaneously from the passive to the active state when the protection current is switched off [12]. The predetermined nominal voltage between reference electrode and protected object is compared with the actual voltage f/j in a differential display unit D. The difference AU = is amplified in a voltage amplifier SV to VqAU. This... 

Power stage with high voltage amplifiers. 

When constituted of metals, thermopiles exhibit a very low noise, in particular only thermal noise if the voltage amplifier used for signal amplification has a very high input impedance. 

Another possible circuit is a voltage amplifier, with a shunt resistor to convert the input current to input voltage (see Fig, 11.1. This type of current amplifier has more disadvantages than the picoammeter The input... 

The insertion of an RC circuit in the feedback electronics right before the high-voltage amplifier for the z piezo has some other advantages. First, much of the high-frequency noise is efficiently filtered out. Second, it facilitates the realization of the electronics for spectroscopic study, which we will discuss in the following section. 

Fig. 14.1. Electronics for local tunneling spectroscopy. By using an op-amp with FET input stage as the isolation amplifier to the high-voltage amplifier for the z piezo, the holding time on the capacitor can be as long as 100 sec. The values of R and C show typical ranges.

Only about 1 in 10s carbon atoms produces an ion, but ion production is proportional to the number of susceptible carbon atoms entering the flame. In the absence of analyte, 10 14 A flows between the flame tip and the collector, which is held at +200 to 300 V with respect to the flame tip. Eluted analytes produce a current of 10 12 A, which is converted to voltage, amplified, filtered to remove high-frequency noise, and finally converted to a digital signal. 

The AC field was generated with a sine wave fed into a high-voltage amplifier (0 10 kV) [25], The frequency and the applied voltage were 5 Hz and 4 kV, respectively. 

Figure 9.6 Experimental setup for measuring the angular distribution of the scattered light at different temperatures and externally applied electric fields. L is a He-Ne-laser, A/2 a half-wave retarder plate, P a Glan-Thomson prism, BS a beam splitter, PDl and PD2 are photodiodes and HV the high voltage amplifier. The sbn sample with 0.66 mol% Cerium is placed on a stack of Peltier-elements to control the temperature.

Fig. 3. Current to voltage amplifier. The output voltage is given by — Tr-Rfb-...

As a result of this excitation step, the net coherent ion motion produces a time-dependent signal on the receiver plates, termed the image current , which represents all ions in the FT-ICR cell. The image current is converted to a voltage, amplified, digitized, and Fourier transformed to yield a frequency spectrum that contains complete information about frequencies and abundances of all ions trapped in the cell. A mass spectrum can then be determined by converting frequency into mass because frequency can be measured precisely, the mass of an ion can be determined to one part in 109 or better. 

Solution This circuit is very similar to an inverting voltage amplifier xmthout resistance Ra in the input line. The input point A is at a lArtml ground potential, and Vo is proportional to the current i.e., Vo = Roi. 

The basic measurement technique for intensity-modulated photovoltage spectroscopy (IMVS) is the same as for IMPS. In principle, IMVS measurements can be made for any constant current condition, but in practice it is usual to make measurements under conditions where the net current is zero. In the case of a photoelectrochemical solar cell, this corresponds to the open-circuit condition, and a high impedance voltage amplifier is used to ensure that a negligible current is drawn from the illuminated device. The output of the voltage amplifier is fed to the FRA, and the remainder of the set up is the same as for IMPS (cf. Fig. 12.26). 

Controllers for piezoelectric tube or tripod scanners require high-stability, low-noise voltage amplifiers. Since piezoelectric materials have a large... 

The output Vo of the power supply first goes to a voltage divider. Here it is in effect, just stepped-down, for subsequent comparison with the reference voltage Vref- The comparison takes place at the input of the error-amplifier, which is usually just a conventional op-amp (voltage amplifier). 

Signals from the transducers and microphones are amplified, filtered, and analyzed. Typically, charge amplifiers are used for the microphones, and voltage amplifiers, for the transducers. High-pass filters are applied to the signals to eliminate low-frequency mechanical noise, such as pipe vibration. The signals are analyzed by either a true RMS voltmeter or a wide-band spectrum analyzer. 

The measuring circuit consists of a bias voltage supply ff, a pair of macroscopic electrodes, which make up the quantum contact under examination, and a serial resistor Pp of 1000 Q as illustrated in Fig. 1. The voltage drop Vp on the resistor Rp is a function of the measured conductance G ,. The piezoelectric device is used to control the backward and forward movement of the macroscopic contacts, between which the nanowires occur. A high voltage amplifier, controlled by a digital... 

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