Engineering Projects

This basic three-terminal device Fixed Output Voltage Regulator is available as either a positive or negative voltage regulator for a large range of fixed output voltages. In figure 1 small capacitor are shown at the input and output of the voltage regulator, because in many applications such capacitors are required to assure stable operation. Ordinarily we can obtain voltage regulators of the required polarity but it is also possible, as illustrated in figure 2, to use a negative voltage regulator to provide a regulated positive output voltage.Similar connection can be…

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Voltage Regulator Description: IC Voltage regulators operates basically in the same manner as discrete circuit regulators. As illustrated in figure 1, the input voltage, usually the rectified ad filtered power-supply output, is applied to the reference circuit and to the op-amp. For optimum regulation, the op-amp must have high open-loop gain and a fairly large common-mode rejection ratio (CMMR). The reference source determines the accuracy of the regulated voltage output. Reference voltages can be provided by such simple device as a zener diode or by more complex multi-transistor circuits, such…

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A precision voltage reference provides a constant, stable output voltage under a wide range of line, load, and temperature conditions. These devices usually work on the principle of bandgap voltage. Voltage drops are produced across two transistor base emitter diodes with unequal current flow. These voltage drops exhibit a negative temperature coefficient (the drop decreases as temperature is increased). However, the difference between the two voltage drops exhibits a positive temperature coefficient. When properly combined to equal a sum of 1.23V (the bandgap voltage), a near zero temperature coefficient is…

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