Operational amplifier equivalent circuit

A galvanostatic perturbation, in principle, can be applied by means of a rather simple electrical circuit, as is represented in Fig. 3(a). (More sophisticated instrumentation, employing operational amplifiers, has been described in the literature see ref. 22). It is only required that the galvanostat resistance, Rg, be large compared with the equivalent cell resistance, so that the current forced through the cell is independent of the cell properties. If the source of electricity is a d.c. source, as in Fig. 3(a), a constant current I — jA will start to flow after the time t = 0 at which the circuit is closed [see Fig. 3(b)]. The effect of this action will... 

FIGURE 3-1 Equivalent circuit representaiion of an operational amplifier. 

FIGURE 2.4 (a) Circuit schematic symbol for a voltage mode operational amplifier, (b) first order linear model of the op-amp, (c) a voltage amplifier realized with the op-amp functioning as the gain element, (d) equivalent circuit of... 

Figure 3-1 is an equivalent circuit representation of an operational amplifier. In this figure, the input voltages are represented by and V-. The input difference voltage IV is the difference between these two voltages that is, IV = - v. The power supply connections arc... 

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