Last night, I taught a small, but enthusiastic, group of Makers about digital multimeters at the Ann Arbor District Library’s Secret Lab. The Secret Lab is a partnership between the library and the University of Michigan, and the library and the university hope it will be a space where people can create, invent and learn. This is the first in a series of electronics classes that I plan to teach there.
Only five people showed up for yesterday’s class, but they were an enthusiastic group. Here’s the outline I used for the class:
Digits and counts
Accuracy
Features to look for
ruggedness
test leads
auto off
CAT safety ratings – safe up to 6,000V
Measurements on a simple circuit
Resistance – resistor
Battery voltage
Current
Voltage – battery, voltages across resistor and diode
Other functions
continuity: cables and connections
diode
non-contact voltage
frequency
capacitance
temperature
The simple circuit was a circuit consisting of a 9V battery, a 330 Ω resistor, and an LED:
Based on my recommendation, thanks to help from you, the library purchased ten Extech 330 DMMs. Each of the students got their own meter, a prototyping board, and the components to make the circuit.
One of the students was a real newbie. She was trying to make a greeting card with a simple circuit that would light an LED. As part of the design, she used conductive ink, but when she folded the card, the continuity was broken. She needed help in understanding the circuit and then how to troubleshoot her problem. I taught her a little bit about Ohm’s Law, and one of the students and I showed her how to check the resistance of the ink and the continuity of her ink. I think that she now understands a lot more than she did before the class.
The ham radio connection
In talking with the students, I discovered that a couple of them had family members who were hams. One guy’s father was a ham, and the grandfather of one of the women was a ham. I gave them my card (which has a link to my free study guide) and encouraged them to get their licenses.
Cool feature
In preparing for the class, I got to play around with the Extech 330 DMM. One of the coolest features, I think, is non-contact voltage detection. This feature allows you to find hot AC lines without actually contacting the line. I used this feature when I installed several outdoor lights in the front of my house. I was able to tell if the circuit was live or not before installing the light fixture.
The Secret Lab is a cool place, and I hope to help make it cooler. I enjoyed teaching the DMM class, and I hope the library thought so, too, and will invite me to teach it again sometime. At some point, I’m also going to be teaching a class on how to use an oscilloscope, and after that, perhaps a basic electronics class. This should be a lot of fun.
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