- 1). Set the momentary switch into the breadboard so that the two terminals protrude through the holes. Set the LM317 voltage regulator next to it, sliding the three terminals through the breadboard as well.
- 2). Turn the breadboard over and use a length of copper wire to connect one terminal of the momentary switch with the "in" leg of the LM317. Solder both of these connections to fix the components in place.
- 3). Solder another length of copper wire to the "adjust" leg of the LM317, making certain that you do not apply so much solder that you short the adjacent leg.
- 4). Set the 100-ohm variable resistor into the breadboard so that the three terminals slide through the holes in the board. Solder the free end of the copper wire connected to the middle leg of the LM317 to one of the outer legs of the 100-ohm variable resistor.
- 5). Plug a 10-ohm resistor into the breadboard close enough to be connected both to the LM317 and to the 100-ohm variable resistor. Turn the breadboard over and take a length of copper wire, soldering one end to a leg of the 10-ohm resistor and the other end to the middle terminal of the 100-ohm resistor.
- 6). Connect one end of another length of copper wire to the other leg of the 10-ohm resistor, and touch the free end of the copper wire to the "out" leg of the LM317. Solder both connections to secure them, taking particular care not to melt the solder on the other legs of the LM317 or to short the connections.
- 7). Slide the second 10-ohm resistor into the breadboard right next to the first one. Twist the legs of the two resistors together so that they are connected in parallel, rather than in series. If necessary, use some solder to reinforce this connection.
- 8). Plug the 1N4001 rectifier and the 10 microfarad 16V capacitor into the breadboard. Using a length of copper wire, connect one leg of the rectifier to one leg of the capacitor, and solder both connections in place. Take another length of copper wire and do the same with the remaining leg of the rectifier and the capacitor.
- 9). Take a length of copper wire and locate the side of the 10-ohm resistor array that is connected to the "out" leg of the LM317. Connect this to one leg of the 1N4001 rectifier and solder the connection (it will now be joined three ways --- the 10-ohm resistor, the rectifier, and the capacitor will all be connected at the same point).
- 10
Set the 3V laser diode into the breadboard. Using a length of copper wire, connect the positive terminal of the laser diode to the leg of the capacitor that is in series with the "out" leg of the LM317. Solder the wire so that the laser diode is wired to the capacitor. - 11
Connect one end of another length of copper wire to the negative terminal of the laser diode, and touch the free end of this wire to the other leg of the capacitor (the one not in series with the "out" leg of LM317). Solder this connection at both ends --- both legs of the 10 microfarad capacitor will now be connected simultaneously to the laser diode and the rectifier. - 12
Locate the end of the rectifier that is not in series with the "out" leg of the LM317 (the leg of the rectifier that is currently only connected to the capacitor next to it). Use a length of copper wire to connect it to the negative terminal of the 7.2V power supply, and then solder the wire at both ends. - 13
Connect the last remaining length of copper wire from the positive terminal of the 7.2V power supply to the free terminal of the momentary switch. Solder both connections.
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