Ph 490

January 6, 2005

 

Problem Set 10

 

 

1.  Consider the resistor divider shown.  Show that the output impedance is given by

,

where the output impedance is defined by

 

 

 

2.  Suppose that a scaler chip puts out signals as shown:  A is at the clock frequency, B is divided by 2, C is divided by 4, and D is divided by eight.  The waveforms are shown.  It is desired to make signals to turn on the red, yellow, and green lights for two streets that cross.  Let's say that the streets are Sloat and 19th.  (The light cycle is to be the standard simple two-way one, though, not the more complicated cycle actually used at the intersection of Sloat and 19th.)

  Find logical expressions for the signals to light all six lights (red, yellow, and green for Sloat and 19th).  Two examples are given below to start you off.