Over the last few posts, we’ve covered everything I wanted to write to you about resistors, what they are, how they work, and the different types based on construction. The series won’t be complete till I cover variable resistors and its following different types
Potentiometers are the most common type of variable resistor. They consist of a resistive track (usually made of carbon, cermet, or conductive plastic) with a movable wiper that slides along the track, adjusting the resistance between two terminals.
Use Case: Volume control in audio systems, brightness control in displays, and manual tuning applications.
Types: Linear (changes resistance uniformly) and logarithmic (better for human-perceived volume control). Digital potentiometers are also there which can be set to a particular resistance value via control signals to it.
Rheostats are essentially potentiometers used as two-terminal devices, where one terminal is connected to the wiper, and the other to one end of the resistive element. They are designed to handle higher currents and are often used in power control applications.
Use Case: Motor speed control, heater control, and lamp dimming.
Types: Rotary rheostats (knob-based) and slider rheostats (lever-based).
Trimmers(Trimpots, covered in great detail in older posts) are miniature, preset potentiometers used for fine adjustments during circuit calibration. Trimmers are usually set once and rarely changed unless recalibration is needed.
Use Case: Calibration of precision circuits, setting reference voltages, and fine-tuning oscillators.
Adjustment Methods: Screwdriver-slotted (single-turn) or multi-turn for finer adjustments.
Variable resistors offer flexibility where fixed resistors cannot and are an important tool in electronics.
And with that, we wrap up this Back to Basics: Resistor Series! Hope this helped you gain a new perspective on one of the most fundamental components. I will discuss something else from next week onwards.
#BackToBasics #Electronics #Resistors
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