This appears to me to be my first legit project, and dare I say the one that I am most proud of yet? No, it isn’t anything special, but this project seemed more involved tech wise than others and when I was done, it worked exactely how I wanted it to.
I subscribe to the MAKE podcasts and on their How-To-Tuesday episodes on 1/28/09, he assembled a Plug-in-Bread-Board Power Supply. Then after some thought I figured that I could really just build the circuit myself, and so I did.
After picking up a variable voltage regulator, I built the circuit on a bread board to see what resistors were need to change the voltage out. Also after reading that data sheet from National Semiconductor, I read that the capacitors that were in the ‘How-To’ build, didn’t really need to be there. Also in there build they had there voltage out being 3.3 or 5 volts. So to determine the needed resistance I used a potentimeter and my multimeter to measure the voltages.
(I forgot about the 3.3 so I was just aiming for somewhere around 3… Oops.)
After assembling and find the needed resistance, I just soldered it all on a board from Radio Shack. One other thing that I happen to like about my build is that I just us a switch to change the voltages. For Make’s power supply they use a jumper which just seems like a little bit more work to change the voltage. I used a SPDT switch that changes the flow of current through to independant sets of resistors. (Just see TOP photo).
(Solder work could be better, just never worked with these boards before. Figuring out how to lay everything out was a challenge/fun.)
Once it was all soldered I just wanted to check and make sure I put in the correct resistors accordingly. I plugged it in and check the voltages.
(The final result…)
If you notice, the board just sits and plugs in so nicely into the breadboard. The only thing I had to do was line up the plugins. If you notice you can see a resistor located on either sides. If you look close enough to the solder work, on the picture above, the resistors aren’t being “used”. Both of their ends are connected and are just there to provide a solid connection to the bread board.
This is a project I would like to rebuild another time. For starters I would like there to be a power switch. Right now, the second you plug it in, it is live. Also, I wish I would have thought about adding a 2 LED indicator lights letting me know which power side is running. Another adjustment I might have done would have been to put a potentionmeter in there so I could always manage and change the voltage. Then again in order to actually know the voltage I would have to measure it everytime.
(3V on the left and 5 V on the right.)