In many situations, the raw output of the sensor may not be in a form suitable to be interfaced to a measurement device or an A/D convertor, and some form of signal conditioning is needed to be applied to the sensor output. These signal conditioning operations include filtering, amplification, or using a bridge circuit. In […]
There are a number of parameters that characterize sensors’ performance. The time-independent characteristics are called the static characteristics, while the time-dependent characteristics are called the dynamic characteristics. The static characteristics characterize the sensor output after it has settled due to changes in the physical quantity being measured. The dynamic characteristics describe the sensor characteristics from
An ideal dc voltage source produces a load voltage that is constant. The simplest example of an ideal dc voltage source is a perfect battery, one whose internal resistance is zero. Figure 1(a) shows an ideal voltage source connected to a variable load resistance of 1 V to 10 MΩ. The voltmeter reads 10 V,
Figure 1(a) shows a boost converter, another basic topology for converters. A boost converter always steps the voltage up. The theory of operation is similar to that for a buck converter in some ways but very different in others. Boost Converter Working For instance, when the pulse is high, the switch is closed and energy
Figure 1(a) shows a buck converter, the most basic topology for converters. A buck converter always steps the voltage down. A transistor, either a bipolar junction or a power FET, is used as the switching device. A rectangular signal out of the pulse-width modulator closes and opens the switch. A comparator controls the duty cycle
Triac Working The triac is a three-terminal device essentially equivalent to two SCRs joined in reverse parallel (paralleled but with the polarity reversed) and with their gates connected together. The result is a bidirectional electronic switch that can be used to provide load current during both halves of the AC supply voltage. Triac connections, shown
Thyristor is a generic term for a broad range of semiconductor components used as an electronic switch. Like a mechanical switch it has only two states: on (conducting) and off (not conducting). Thyristors have no linear in-between state as transistors have. In addition to switching, they can also be used to adjust the amount of
Refrigeration| MCQ 1. A one tonne refrigerating machine means that (a) the total weight of the machine is one tonne. (b) the quantity of the refrigerant used is one tonne. (c) one tonne of water can be converted into ice. (d) one tonne of ice when melts from and at 0°C in 24 hours, the
Ammeters and voltmeters affect the operation of circuits. The degree to which the circuits are affected is called the loading effect of the instrument. For an instrument to provide an accurate indication of how a circuit operates, the loading effect should ideally be zero. In practice, it is impossible for any instrument to have zero
Removal of moisture and impurities from insulation is one of the most important manufacturing processes. Removing moisture from the oil is relatively simple, which can be done by conventional methods of filtration or heat/vacuum cycles. However, most of the moisture is in the solid insulation (it can be as high as 99%). Hence, a challenge