mas.s60: problem set 1 - due 9.19.12

problem 1:  you will recieve a pcb with components on it.  draw out the schematic for this pcb.  please include the values of all the components.  if you do not know what some of the components are, just draw a good representation of the part, and label it with as much information as you have.  there is a drawing of the board here:

http://web.media.mit.edu/~geppetto/vids/pcb1.png

it has labels for all the parts.  include the labels on your schematic.

problem 2:  you will recieve the first part of your lab kit in class.  this should include:

1 protoboard
1 power supply
1 power jack
4 .1uF capacitors
2 100uF/25V capacitors
1 7805 voltage regulator
1 green LED
1 red LED

A. place the power jack into the protoboard, and run 2 wires from its power pins to an open section on the protoboard.  next, hotglue the power jack in place.  there is a picture of what this should look like here:

http://web.media.mit.edu/~geppetto/vids/protobard1.jpg

there are 3 pins on the power jack, be sure you get the right 2, and that the polarity is correct.  you can check this with your multimeter.  you will want to make sure it is correct before hotglueing it in place.

B. what is the voltage coming out of your powersupply?  is this AC or DC? can the 7805 handle this level of input voltage?

C. build a 5V powersupply on your protoboard using the 7805, 100uF, and .1uF capacitors.

D. if you were to connect a 100ohm resistor between 5V and ground, how much current would be flowing through the resistor?  can the 7805 handle this much current being drawn from it?  how much power would the 7805 be burning under these conditions?  how much power would be going through resistor?

problem 3:  pick appropriate resistor values for your red and green LEDs, such that the LEDS have 10mA going thorugh them.  write up a justification for your value.  find resistors of those values, and light up your LEDs.