TABLE OF CONTENTS Electronic circuits contain amplifying devices used to adjust the signal level depending on the characteristics required by the user. This is particularly true for analog and measurement electronics. A person listening to a stereo system can adjust the sound volume by modifying the amplitude of the source signals fed to the amplifiers. The measurement of a physical phenomenon by means of an electronic device takes place in such a way that the amplitude of the input signal representing the phenomenon is modulated as a function of the characteristics of the measurement circuits. This modulation can take place through the use of a potentiometer. We can represent a component of this type schematicallyby a voltage bridge in which V is the input signal and v the output signal:
Here, R 1 + R 2 = R T is constant while R 1 and R 2 vary continuously.
Under other circumstances the change in R 1 can be linked to the movement of an object, such as a piston; the position of an air intake valve on a carburetor; the expansion of a mechanical part with temperature, or any other limiting factor. In this case we speak of apotentiometric position sensor. Below, we discuss the design of such components, their performance, and their operating conditions.
There are two main types of variable resistors: potentiometers and trimmers. Whereas potentiometers are generally devices that respond to variations in an input...
