Make: Electronics – Chp 1 Exercise 4

Exercise four “Varying Voltage” is an introduction to the manipulation of voltage via a pot (potentiometer).Experiment_four

One of the initial requirements of this exercise is to dismantle a pot and perform a visual inspection of its inner-workings.  Personally, I am not a fan of ruining a perfectly functioning component. However, if you are careful, it is pretty easy reassembling the pot.

Experiment_four_bA DMM is used to reveal the resistance bandwidth of the pot.  My pot in particular is rated at 2K but the DMM revealed it to be slightly higher – expected of course.

Another aspect of this exercise is to develop a simple circuit that includes a battery source, pot, and a LED.  You must ensure that the pot is turned to its lowest setting in order to prevent blowing up the LED. Of course I had my pot turned too far the wrong way and blew the first LED.Experiment_four_c

Interestingly enough, you are taught how to include your DMM in the circuit in order to measure current. This however can have consequences for the beginner who is not paying attention or does not grasp the concept of what is actually happening. Blowing a fuse in your DMM may result if you are not careful.

Overall, this exercise is very complete and provides quite a bit of background topics including electronics fundamentals, e.g., series and parallel, using Ohms law, mathematical formulas, and how to read a datasheet just to name a few.

Required Components:
2K Linear Potentiometer (2)
LED (2)
Alligator Clips



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