Transducer terminology question

AI Thread Summary
The output signal of a rotary potentiometer measuring angular displacement is voltage, as it reflects changes in resistance due to the position of the contact within the potentiometer. While the potentiometer acts as a variable resistor, it is powered to produce a variable voltage output, which is advantageous for signal transmission. The output device, such as a digital multimeter (DMM), measures this voltage signal, not the physical angular displacement itself. Understanding the relationship between resistance, voltage, and the components of the transducer system is essential for accurate interpretation of the output signal. Overall, clarity on these parameters enhances the effective use of transducer systems.
StonieJ
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If you have a rotary potentiometer that measures the amount of angular displacement, what would you say the output signal of the transducer is? I'm unsure if it's resistance or voltage. A change in angular displacement changes the point of contact within the potentiometer, which directly affects its resistance. However, in our case, we are measuring the change in voltage over the potentiometer with a DMM. Actually, there is a list of parameters we need to figure out, and this is what I've come up with.

Input Signal to Transducer: angular displacement
Output Signal from Transducer: voltage
Output device: DMM
Output of the sensing system: resistance

I'm mainly just confused with the many different types of output. I would think the transducer is the "big picture" (of which our important quantity is voltage), while the sensing system is the potentiometer itself, which changes its resistance. Then I just figured that the output device is whatever your measuring the change with.
 
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StonieJ said:
I'm mainly just confused with the many different types of output. I would think the transducer is the "big picture" (of which our important quantity is voltage), while the sensing system is the potentiometer itself, which changes its resistance. Then I just figured that the output device is whatever your measuring the change with.

You're pretty much correct. Even though the pot. is a variable resistor, you power it so that you get a variable voltage as the actual output signal. The voltage has a lot of benefits, especially if you have to carry that signal over a distance or if you don't have resistance measuring devices.

The two transducer outputs you'll see the most of are voltage and current outputs. The standard current output is a 4-20 mA signal. There are others such as a frequency outputs.

To answer your original question, the output signal is a voltage signal. The signal you actually measure is what that refers to, not the physical "thing" you are measuring, like angular displacement.
 


It seems like you have a good understanding of the different components involved in this transducer system. The output signal from the transducer is indeed voltage, as this is what is being measured with the DMM. The resistance of the potentiometer is a crucial aspect of the transducer, as it is what is being changed by the angular displacement and ultimately affects the output voltage. The DMM is simply the device used to measure the output voltage, so it can be considered the output device. Overall, it is important to understand the different parameters and components involved in a transducer system in order to accurately interpret and utilize the output signal.
 
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