Basic Electronics Lab
I had brought a power supply from home to try to use on this project. It was rated at:
120V IN
9V OUT
400 mA
The dongle of the power supply didn’t fit with the provided plugs from the cabinet so I decided to just clip off the end of the power plug and try to wire it in myself. I used the multimeter to figure out which end was positive, soldered some leads onto the two wires from the power plug and finally glue gunned the whole thing. It didn’t work. With Caryln’s help, we decided that the power supply was faulty. I ended up borrowing someone else’s 12v for the work.
I completed all the projects. I took a few photos and will attach them to the bottom of this page. Here are some notes for interesting things that came up with particular steps:
Step 2
The circuit lit up two lights but the third one didn’t light up. Since the lights were acting as resistors, they convert electricity to heat and light. The circuit was only five volts due to the voltage regulator and that wasn’t enough power to light up three lights. I tried putting resistors between each one of the lights but that didn’t help. When I took each of the lights, gave each of them their own resistor and ran them directly to power they all worked. I think I have demonstrated the concept of serial versus parallel but i’m not completely clear on that. I think seeing a physical parallel versus series circuit would be useful, not just a diagram.
Questions:
Part of my original problem was that I was misreading (or getting malfunctioning) multimeters and I just assumed there was something wrong with the circuit. I’m not clear on all the extra switches on the multimeter and need help using it. I think other students have the same problem. Our circuits worked but without fully understanding the multimeter we cannot debug them intelligently, only with trial and error. Right now they are very simple but that won’t work for the more complicated ones.
I am also not clear on what the output is on the voltage regulator since my understanding is the whole circuit becomes five volts when the regulator is added. Other students weren’t even using the output on the voltage regulator (just power & grnd) which defeats the purpose of it, right?
3 Photos from the lab. Once i got into it I forgot to take pictures.
