Sep. 13
   
Assignment Journal 01
   
 
First I was quite nervous about what I was going to do. I spent a lot of time trying to get all those parts together: NYU computer center, Radio Shack at 9th St, 14th St, and Newport Mall, I bought stuff and returned them....Finally, I brought what I got to the shop, sat down tightly on my seat, and, what's next?

At first it was in a mess, I didn't know where to start. Then I got to know this circuit thing and started to have fun with it.

Soldering

At first I spent a lot of time soldering. I just couldn't do it right. Then I happened to have this chance to see someone soldering, then I got the idea (Sorry I forget your name).

What I did originally was to heat up the soldering iron and started to melt some solder on it, and then I pointed it to what I wanted to solder together. And it always turned out the melted solder attached to the iron instead of the wires and it formed a very ugly shape. What's worse is it was not clinging together so it got pulled off easily.

Later I found out, before I solder wires together, I use the iron to heat up what I want to solder, and then I put the solder near it, so that as soon as it melts, I can apply it to the wires immediately.

Build the circuit

I started with a circuit without anything on it. There were only regulators, lines leading in power, and lines that go around the board, a closed circuit. Then I put the switch into the circuit, of course between the "in" and "out" points. Where the "out" point of the switch went was the place I wanted to build other circuits. So I lead it out to 2 directions, to make a parallel connection. Each will have 220 ohm resistors and a LED. This one was simple; as long as they formed a closed circuit separately, it worked. When the power was on, they both lightened; when it was off, the lights went off.

 
  step1: control the LEDs on the left side with the switch  

Variable Resistor

Then I saw Yuriko using a variable resistor as a switch between two circuits, I felt like trying one myself. On the other side of the board, before the switch, I put the variable resistor in. I formed two circuits separately and they were supposed to work as two teams. When I turn the resistor, they should light up in turns. It turned out they always lighted up at the same time and the regulator got REALLY hot. I couldn't find out why so I just took off the resistor. Now they were working OK only I couldn't have that result I planned.

 
I took off the flexible resistor and arranged the right parts in a serial circuit  

Follow up:

I found out that the problem with my Variable Resistor. It has three "legs" and we used to think the middle one is for "ground". However, it is different here; the middle one should be connected to the "power". The other two legs are connected to parellel circuits. That's how it directs the power from one to the other. That is where the problem is.

see the chartchart


See the black one(the middle one should be connected to the power source and the other two lead to different independant circuits. So when I turn the resistor, the lights go on and off accordingly.)