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Construct the parallel circuit, put it all together

A detailed demonstration of how to build this project, from beginning to end. Created by Exploratorium.

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Video transcript

- [Voiceover] First, I drilled the holes in the breadboard, the pine board. And now I'll have to screw in the screws and the washers. So let's put this all together. I'm gonna start by attaching a red lead on this side and one of the flattened alligator clips. So they all go to the same connection, so we'll tighten them together. And then on the other side, representing the negative end of the battery, I'll use a black lead and another flattened alligator clip. The black lead is gonna run over here, and it's gonna attach in the same place that our paper clip switch adapter attaches. So here we go, here's our paper clip on that side. Oh, I forgot to put in the 470ohm resister and the black lead from the 9-volt battery power connector. So let me get both of those put together. Sometimes in these projects, you do need three hands. And plug this into here. Okay, now we've got the negative leads all connected. The light-emitting diode has a long leg and a short leg, and the long leg should definitely go to the positive red lead from the battery. The battery, I've connected it to an alligator clip, an optional alligator clip, to act as a switch. You don't need to do that. You can run it straight to a stripped wire. And then on this side we'll finish up the positive connections with a paper clip and the positive lead. Okay, so we have our mono phono jack, and we're gonna need to cut one end off and replace it with alligator clips. So I'm gonna take my wire strippers and cut off the outer insulation. Now you might notice this spray of copper wires around the outside. This copper wire wraps all the way around the inner insulated wire, which is our signal. And by wrapping a conductor completely around a signal-carrying wire, you can shield it from outside interference. So this is a very nice system. Now we'll get in here. The inner wire, and now we can crimp those into our alligator clips. You could solder these to make it a more permanent connnection. Again, three hands helps. Okay. We'll get these all ready to accept our wire, we'll put the shielded one. I'm twisting the leads so that they hang together better. And there is a little hole. If I can get it through the hole, that's nice. Ah, there we go, I got it through the hole. That makes it wind around just a little bit more. Okay, so now I will crimp these together. Okay, so now I've made my mini phono plug to alligator clip connector. So let's put it all together. I'm gonna attach the battery. The positive side to the battery is on the red wires, the negative side is on the black wires. I'm now gonna check my LEDs, so I'll take the LED, the long leg goes to the red positive lead, the short leg goes to the black negative lead. Now I'll close my switch with the optional alligator clip, and the light is on, so we have power. I'll disconnect it for the moment. Now I'll turn on my radio (radio playing) and when I plug in my mini phono plug, it disconnects the speaker on the radio and sends the signal to these two leads. Now this is an A/C signal, so it doesn't matter which lead I connect to which side. Now I'll connect my detector. So I have my solar cell, it's also gonna pick up an A/C signal, so it doesn't matter which lead I connect to which terminal of the solar cell. I'll plug that in to the amplified speaker input, turn on the amplified speaker, and now I'll light the LED. (radio static playing) There is sound coming over.