Voltage-controlled current source

HlfiT Hi is a current-controlled voltage source. The voltage of Hi is 8 times the current through R2. SOLUTtOn Add a print part and fill it in as shown ... 

Node label Current-controlled voltage source ... 

FIGURE 23 Circuit schematic symbol for (a) voltage-controlled voltage source (VCVS), (b) current-controlled voltage source (CCVS), (c) voltage-controlled current source (VCCS), (d) current-controlled current source (CCCS). 

The setup uses a source of... controlled current controlled voltage... 

In previous sections, we described the conventional op-amp and examined some of its applications. In this section, we survey other important operational elements—the current feedback op-amp (CFB), the operational transconductance amplifier (OTA), and the current conveyor (CC). All of these other operational elements are available commercially, and aU offer advantages and have some disadvantages in comparison with conventional op-amps such as the /xA741. Unlike the conventional op-amp, which is a voltage-controlled voltage source (VCVS) operational element, current is the main variable of interest at either an input or an output port of all the other operational elements. 

To construct N given N, voltage-controlled-voltage-sources in N are replaced by current-controlled-current-sources in N with input terminal pairs of the sources exchanged with output terminal pairs as shown in Fig. 7.147. Passive elements R,L, and C are left unchanged. The resulting networks are termed... 

FIGURE 7.147 Voltage-controlled-voltage-sources are replaced by current-controlled-current-sources with input and output terminal pairs exchanged to obtain N from given network N. 

The inverter may be a current source inverter, rather than a voltage source inverter (.Section 6.9.4) since it will be the rotor current that is required to be vtiried (equation (1.7)) to control the speed of a wound rotor motor, and this can be independently varied through the control of the rotor current. The speed and torque of the motor can be smoothly and steplessly controlled by this method, without any power loss. Figures 6.47 and 6.48 illustrate a typical slip recovery system and its control scheme, respectively. 

Alternatively, one may control the electrode potential and monitor the current. This potentiodynamic approach is relatively easy to accomplish by use of a constant-voltage source if the counterelectrode also functions as the reference electrode. As indicated in the previous section, this may lead to various undesirable effects if a sizable ohmic potential drop exists between the electrodes, or if the overpotential of the counterelectrode is strongly dependent on current. The potential of the working electrode can be controlled instead with respect to a separate reference electrode by using a potentiostat. The electrode potential may be varied in small increments or continuously. It is also possible to impose the limiting-current condition instantaneously by applying a potential step. 

For current-controlled conversions, a current-regulated DC source (up to 50V and 2A, with voltage and current display) [175] or one or two car batteries (12 to 24V) with a volt and ampere meter [176] or a regulated AC power source with a rectifier are sufficient as the power supply. 

Figure 3. Examples of the NESS, (a) An electric current / flowing through a resistance R and maintained by a voltage source or control parameter V. (b) A fluid sheared between two plates that move at speed v (the control parameter) relative to each other, (c) A chemical reaction A — B coupled to ATP hydrolysis. The control parameters here are the concentrations of ATP and ADP.

The pulses are provided by a precision bipolar voltage source, which is switched into the input of the pulsing amplifier by the switch at point A in the circuit. A very accurate crystal-controlled timing circuit (not shown) drives the switch to ensure that the pulses are symmetrical. The pulsing amplifier inverts the signal as shown by waveform B and supplies current to the cell. The cell current is amplified by the current follower, the output of which is illustrated by waveform C. 

The circuit under consideration consists of a normal coherent conductor with conductance G in series with the Josephson junction(system) (Fig. 1). The system is biased with voltage source V k T/e. This assures that the normal conductor is in the shot noise regime. In addition, we inject extra current p that controls the slope of the Josephson washboard potential. 

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