EE70L Lab 1

Objective:
1. To become familiar with the lab equipment (Digital Multi Meter -DMM-, Oscilloscope, etc.).
2. To verify Kirchoff's Laws.
3. To design and test a simple voltage divider

Figure 1

1. Using a Digital Multi Meter (DMM), measure the following resistor values:

Table 1

HINT: Place RED probe of the DMM on one lead of the resistor and the BLACK probe on the other lead. Polarity does not matter.

2. Measure the following voltage drops.

Table 2

HINT: V_AB is the voltage drop from point A to point B. This is equivalent to VAB. Place the RED PROBE on node A and BLACK probe at node B.

3. Mesure node voltages

Table 3

HINT: To measure node voltage at node A (V_A or VA) Place BLACK probe at node D (ground) and place RED probe at A.

4. Measure the currents

Table 4

HINT: There are more than one way to measure current.
Method 1: Break open a path and place the DMM in series the components of theat path as shown below

Figure 2: Circuit 1 with DMM in series to measure I1 (or I2)

OR

Method 2: Measure voltage drop across a resistor and divde the voltage drop by the measure resistance. BOTH methods will find current through R1.

5. Verify Kirchoff's Current Law (KCL)
There are three path currents associated with node B.

a. I2 + I3 + I5 = _______
b. Does Kirchoff's Current Law hold for node B? yes/no
c. What is Kirchoff's Current Law? (State in your own words)

d. What is the relationship between I7 and I8? (a simple equation will do)

6. Verify Kirchoff's Voltage Law (KVL)

Measure the following voltages: 

Voltage	Value
V_AB
V_BD
V_BC
V_CD

a. V_AB + V_BD - V1 = _______volts

b. -V1 + V_AB + V_BC + V_CD = _______volts

c. Does V_BD = -V_DB? (yes/no)

d. V_DB + V_BC + V_CD = _______volts

7. Measure V1 as indicated on Figure 1.

V1 = ________volts

How did you measure V1 with the DMM? (Fill in blanks)
Place RED probe at node ____
and BLACK probe at node ____.

8. AC Measurements
This part of the experiment will help you become familiar with the oscilloscope, frequency generator and the frequency counter.

Connect the frequency generator, DMM, oscilloscope, and frequency counter as shown below:

Figure 3

Select the sinusoidal waveform mode. Adjust the frequency of the generated signal to 1KHz or 1000Hz. Adjust the amplitude of the generator if desired.

Fill in the answers below:

DMM
RMS value = _______ volts

Peak value, calculated = (RMS value) * 1.414 = _________volts

Oscilloscope
vertical scale = __________________ (be sure tinclude units per div)

vertical divisions = ________________ divisions

peak value = ______________
Hint: vertical scale * vertical divisions = peak value

horizontal scale = __________________

horizontal divisions = ________________ divisions

period = ______________

frequency = 1/period = __________________

frequency generator dial setting = ________________

Frequencey Counter 

Counter frequency = _________________

9. Voltage Divider
Design a simple voltage divider , for VB/V1 = 0.5

Figure 4: Simple voltage divider

Hint: (a) Calculate the current in the loop ABD as a function of R1, R2 and V1. (b) Calculate VB. (c) Determine R1 and R2 so that VB/V1=0.5 .

Build your circuit and measure VB and V1. Does VB/V1 come close to 0.5? (yes/no).