EET2010 LAB3

EET 2010 Lab Exercise #3 Electronics Principles

1

Zener Regulators

In this lab you will construct a regulated DC power supply. You will observe the behavior of the

circuit as a function of load current.

Equipment

1. Transformer

2. Oscilloscope

Materials

1. (4) 1N4002 Diodes

2. 10 F Capacitor

3. 1N5230 Diode (Zener)

4. (2) 1 k Resistor

5. (1) 680  Resistor

Procedure

1. Open Multisim (draw the circuits) and Benchvue (take the screenshots)

2. Measure all (3) resistor values and record them.

R1 = RL1 = RL2 =

3. Configure the circuit in Figure 3-1 above.

4. Measure the secondary voltage. Record the rms or peak voltage. Vsec =

5. Determine the turns ratio of the transformer. n =

6. Use the oscilloscope to measure the max and min of the ripple voltage (Point A) of the

filter (Channel 1) and the max and min output voltage (Point B)(Channel 2). Take a

screenshot and save.

7. Calculate the peak currents, IR1, IL, and IZ. (Hint: Start with 𝐼𝑅1 = 𝑉𝐴(𝑝𝑘)

𝑅1+𝑅𝐿 )

8. Replace RL with the 680 Ω resistor and repeat steps 5 and 6.

Figure 3-1

EET 2010 Lab Exercise #3 Electronics Principles

2

Submittal:

1. Lab Cover Sheet (filled in appropriately)

2. Title Page (Appropriate information is described in the ‘Format of a Technical Report’

found on Blackboard)

3. DATA section including:

a. Circuit #1

b. Circuit #2

c. 1N5230 Datasheet

d. Table 3-1 includes nominal and measured values of R1, RL1 and RL2.

e. Table 3-2 includes Vr(p-p) and Vout when RL = 1k  (measured quantities)

f. Table 3-3 includes Vr(p-p) and Vout when RL = 220  (measured quantities)

g. Table 3-4 includes values for IR1, IZener and ILoad for each circuit (calculated

quantities from measured Voltages and Resistances)

h. Sample Calculations includes the general format of equations used to calculate

IR1, IZener and ILoad in Table 3-4.

i. An answer to the following question: “What effect does lowering the load

resistance have on the regulation of the circuit?”

4. DISCUSSION section – makes sure to include discussion regarding measured values

compared to datasheet information.

5. CONCLUSION section

Hint: For a successful submittal make sure your report components are presented in the above

order. This makes organized and logical sense for an explanation of data. Be sure headings are

stated (for example: DATA) and all components of the DATA section (for example: TABLE 3-1)

are labeled.

BONUS (10%): Simulate both circuits in Multisim and make a comparison of measured to

simulated results of ripple voltage and regulated output voltage.