11-Triac

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Triac.doc print name (first last): ______________________

course: EET 257 11/03/2005

lab date (mo/day/yr): ______________________

lab section (day time): ______________________

instructor: ______________________

Power Controlwith the Triac

Performance Checks

_____ 1. V load waveform for 65% duty cycle time proportioned zero crossing (2.j.)

_____ 2. V load waveform for V load RMS measured = 75V voltage controlled phase angle firing (3.n.)

Lab Report Scoresheet

Prelab initial submission (on time, with calculations, complete) (15%) _________

Prelab correction of all marked errors (due with report) (5%) __________

All required signed Performance check offs (35%) __________

Lab Report Purpose, Approach and Results (35%) __________ Proper grammar, capitalization, spelling -2% each error Any other errors -3% each error

Lab Report Analysis and Conclusions (10%) __________ Proper grammar, capitalization, spelling -2% each error Any other errors -3% each error Questions not answered in the form: 1. xxx, 2. yyy -3%

Total __________

Late PenaltiesLate to lab (-1%/min) ___________ Late report (* 0.5) ___________

Final Report Grade %, (maximum = 100%) __________ Comments:

No-report Challenge

initials

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EET 257 - 2 - Power Control with the Triac

Prelab Calculations

1. Obtain a copy of the specifications of the Teccor Q4004L4 triac. Attach those specifications to thereport.

2. Draw the package for the Q4004L4 and identify the MT1, MT2 and the gate.

3. Is the package isolated? __________

4. Draw the schematic symbol and identify MT1, MT2 and the gate.

5. From the data sheet, find the following:

a. maxdd

t v

= __________secV

(off state voltage)

b. maxdd

t i = __________

secA

c. V DRM = __________V RMS

d. I TSM = __________A RMS

e. V TM = __________V

6. Assuming that the load is a 135W light bulb, calculate the following:

a. Rlight bulb = _____

b. I light bulb = __________A rms

c. P triac on = __________W

d. T J = __________ C (assuming T A = 30 C, JA = 50 C/W

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Objectives

Verify the performance of a triac operated with three drivers; simple ON/OFF, time proportionedzero crossing, and phase angle firing with a monostable multivibrator.

Approach and Results

1. Simple ON/OFF Control

a. Obtain a Triac-Light Control box.

b. With the boxs power cord unplugged , remove the plexiglass cover. With the Ohm meter, verifythe proper configuration, as shown in the shaded box of Figure 1. Do not connect the 5V supply.

Figure 1 Simple ON/OFF control

c. Install your triac and your MOC3030 (or 3031 or 3032). Be sure that you have each installedcorrectly in their sockets.

d. Pull the ground clip for your oscilloscope x10 probe back and tape it to the cable so that it cannotfall into the circuit. Connect the probe from channel 2 to the light (marked Load ). There is a testpoint available.

Warning Assure that the probe is set to attenuate the voltage to the oscilloscope x10 . This lowersthe voltage to the oscilloscope to about 17V P . Without the x10 attenuator, the input voltage to the

oscilloscope will be 170V P , which will damage the input channel of the oscilloscope

MOC30301

2

6

4

Red

Black

+5VMOC3030

1

2

6

4

N

H

G

Red

Black

+5V

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e. Set the switch on the box to off . Replace the plexiglass cover. Install the light bulb.

f. Connect the +5V supply and common as shown in Figure 1.

g. Plug the box into the line voltage. Turn the +5V on . Set the oscilloscope channel 2 to display theRMS and DC (mean) of these signals.

V load = ___________V rms light ___________ ( on or off)

h. With an insulated tool, flip the switch to on .

V load = ___________V rms light ___________ ( on or off )

i. Turn the +5V supply off. Verify that the light goes off .

j. Unplug the box.

2. Time Proportional Zero Crossing Firinga. Build the circuit shown in Figure 2.

Figure 2 Time proportional zero crossing firing

b. Leave channel two of the oscilloscope, with its ground clip taped back , set to x10, and connectedto the light. Set it to display the rms of the load voltage.

c. Connect channel one of the oscilloscope to display the voltage from the function generator, with its

0V level across the middle of the lower half of the screen. Trigger on this channel. Display> 1 cycle of the input. Measure and display the frequency and the + duty cycle of channel one.

d. Set the function generator to provide a positive going pulse, TTL compatible level, at 6 Hz, with a20% duty cycle.

e. Turn the +5 V dc power supply on . Flip the switch in the triac box on . With channel two of theoscilloscope, verify that the signal at the collector of the transistor is correct.

MOC30301

2

6

4

N

H

G

Red

Black

+5V

R base6.8k

Q12N3904TTL

levels

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Figure 3b Negative going zero crossing pulse

c. Add the 555 configured as a monostable multivibrator, as shown in Figure 3c. Set R t = 39k .With the x10 probe on channel 2, verify that the output is triggered at the zero crossing of thetransformers secondary voltage (point A), and is high for about 4 milliseconds.

1N400x

25.2V RMS

R11k

zero crossingtest point

A

gnddischargethreshold

controlreset

triggerVcc

out

8

1

3

765

42

555

+5V

+5V

0.1

Ct0.1

R t 39k 120V RMS

1N4732A

Rzener4.7k

Figure 3c Zero crossing triggered monostable multivibrator

d. Add the E control as shown in Figure 3d. You may use the other supply from the HP triple powersupply. Vary it between 0V and 5V. With the x10 probe on channel 2, verify that the width of thepulse from the 555 alters smoothly from ~0msec to more than 9msec.

1N400x

25.2V RMS

R11k


A

gnddischargethreshold

controlreset

triggerVcc

out

8

1

3

765

42

555

+5V

+5V

Ct0.1

R t 39k 120V RMS

1N4732A

Rzener4.7k

Econtrol0V to +5V

Figure 3d Voltage controlled monostable multivibrator

e. Add the remaining components as shown in Figure 3e. Be sure to unplug the box , open theplexiglass cover, remove the MOC3030, and replace it with the MOC3010 (or 3011). Then,replace the cover and plug the box into 120 V rms .

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f. Move the oscilloscope channel with the x10 probe to the light, and assure that there is only one ground connection to the oscilloscope.

1N400x

25.2VRMS

R11k


A

gnddischarge

threshold

control

resettrigger

Vcc

out

8

1

3

7

6

5

42

555

+5V

+5V

C t0.1

Rt 39 k 120V

RMS

1N4732A

Rzener4.7k

Econtrol

0V to +5V

MOC30101

2

6

4

N

H

G

Red

Black

Figure 3e Voltage controlled phase angle firing

g. Set channel 2 of the oscilloscope to display the rms of the voltage across the load.

h. Set E control to 2.5V. Plug in the light box. Move channel 1 at the 555s output (measure t high ), andchannel 2 across the load (measure V rms ). Verify that the waveform across the load is correct.

i. Complete a table similar to the one below. Setup the table using Excel now . Enter the data directlyinto the spreadsheet. Do not write the numbers below.

Table 2 Voltage controlled phase angle firingV load measured

Vrms E control

Vdc t lag

msec lag

degrees(calculated)

V load theory Vrms

[Hint: use the curve ]

error inV load %

255075

100

j. Save the V R load waveform with V load rms measured = 75V so you can include it in your report.

Demonstrate the load waveform and the Excel table to the lab instructor at V load rms measured = 75V.

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No-report Challenge

Design1. Design a circuit that will produce a dc voltage to input into the E control input of Figure 3e.

2. The input to your circuit will be 0 V dc to 5 V dc .

3. The output of your circuit should be 5 V dc to 0 V dc . That is, the input is inverted and shifted up 5Vdc . This will produce a direct relationship between this input dc and the power applied to thelight.

Hint: Look at the Zero and Span lecture part of the ECET 368 course web site. Its really just aninverting summer.

Performance1. Verify that the circuit you designed outputs a dc that matches the requirements of steps 2 and 3

above.

2. Connect the output of your circuit to the E control input of the circuit in Figure 3e.

3. Connect the input to a DC supply. Vary it from 0 V dc to 5 Vdc and verify that the lightsbrightness changes directly with the input voltage.

4. Demonstrate this performance.

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Analysis and Conclusions1. Time Proportional Zero Crossing Firing

a. Include Table 1 in the body of your report, immediately following the description of theprocedures.

b. Include the graph of the waveform of the V R load at 65% duty cycle.

c. Explain one application when you would choose this firing technique, and one for which thistechnique is not appropriate.

2. Phase Angle Firing with a Monostable Multivibratora. Include Table 2 in the body of your report, immediately following the description of the

procedures.

b. Plot E control , (X axis) versus V load rms measured (Y axis).

c. Include the graph of the waveform of the V R load at V load rms measured = 75V.

d. Did this circuit behave correctly? Explain.

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11-Triac