‫Welcome to the potentiometer interface explain to lecture in this lecture I'm going explain how potentiometers
‫can be interfaced with an FPGA.
‫One is a potentiometer potentiometer is simply a variable resistor.
‫They're analog in nature so we cannot directly connect the output potentiometer to an FPGA to see that
‫signal that pj's are digital and potentiometers are analog so we need the ADC or analog to digital controller
‫to interface the FPGA with a potentiometer where we use a potentiometer for why we need a variable resistor.
‫Well most commonly they're used to control things such as the volume like in your car or on your stereo
‫system.
‫If your take a switching or turning it slowly that is most likely a potentiometer that you are interfacing
‫with.
‫He also used the like a home lighting application where if the light switch and you want to dim the
‫lights or turn them almost off or almost all the way on that is a potentiometer just more of a linear
‫sliding potentiometer versus the typical ground twist style or like any other type of application you're
‫home you'll see refrigerators or any sort of knob you have to turn is most likely or commonly a potentiometer.
‫So how does a potentiometer actually work.
‫So if we're turning the potentiometer we're either increasing or decreasing the resistance.
‫Well what does it have to do when we do an analog to digital conversion because we're waiting the voltage
‫So how does changing the resistance have anything to do with that.
‫That's a very good question.
‫And the way my change of resistance how that actually affects the voltage is due to Ohm's law which
‫Ohm's law states the is equal to I r where me is equal to your voltage by is equal to your current An
‫our is equal to your resistance and your voltage is involute your current is in amps and your resistance
‫is in ohms and this directly is a formula that just kind of interacts how voltage current and resistance
‫all interact together.
‫So if we look at what is actual or by by varying the resistance we're actually directly changing the
‫voltage which is what we're reading.
‫So when we do a voltage reading every time we change that resistance or turn or potentiometer or voltage
‫reading is going to change or the voltage signal that we're sending into our analog to digital controller.
‫And so that's how we can actually interface an FPGA with an analog signal that is output from the potentiometer.
‫Now you understand how potentiometers operate.
‫Let's get started on the lab.