ABSTRACT
In analog electronics, voltages and current represent variables that vary continuously from the allowable minimum to the maximum. These variables are measured, amplified, added, and subtracted through analog circuits to achieve the desired results. For instance, measurement of temperature using thermocouples requires the amplification of voltages generated to a suitable range, calibration of the voltage with measured temperatures, and outputting the results on a voltmeter to indicate temperature. In this design, it may be necessary to subtract an offset voltage, multiply with a gain factor depending on the temperature range. The amplification of voltages and current are accomplished easily with operational amplifiers and transistors, respectively. The measured temperature can be used as the feedback signal in a control loop for a mechatronic temperature control system. In digital electronics, the variables assume a binary state, assuming a value of 0 or 1. In the above example, we might want to shut the solenoid valve down if the temperature was below desired value and open the valve if the temperature was above that value. In this case, we simply require a TRUE or FALSE input to the question “Is the temperature above or below the threshold?” The representation of these types of variables in circuits, which assume binary values, and their manipulation to achieve desired results is the topic of discussion in this chapter.
