EEET 205 Lab - 102 [PDF]

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Experiment # 1 The SCR and RC phase control Student Name: _________________ Student ID: ____________________ Date: _________________________ Score: Reading: Timothy, Modern Industrial Electronics, Chapter 4, Section 4-1 to 4-5

Objectives: 1. Testing an SCR with ohmmeter. 2. Understanding the gate triggering modes of SCR (the supply voltage is AC ) 3. Understanding the gate triggering modes of SCR (the supply voltage is DC )

Apparatus: -

Power supply unit KL-51001

-

Isolation Transformer KL-58002 Oscilloscope

-

Module KL-53003

-

Analog Multimeter

-

Oscilloscope

Summary of theory: The silicon-controlled rectifier (SCR) is the most important thyristor in the family of PNPN devices. It was developed by General Electric in 1957. The SCR acts as a switch in an AC power control circuit. The SCR is a PNPN four-layer device having three terminals: anode (A), cathode (K), and gate ------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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(G). In most control applications, the control signal is applied between the gate and the cathode while the load is connected to either the anode or the cathode in series. When the gate is open and a forward voltage is applied between the anode and cathode (terminal A is positive with respect to terminal K), the SCR is in off state due to the absence of base currents of transistors Q1 and Q2. The two conditions must be met to fire an SCR. They are: 1. Anode voltage should be positive with respect to the cathode. 2. Gate voltage should be positive with respect to the cathode. The gate has no control over the SCR once it goes into conduction. Turn-off must be achieved in the anode-to-cathode circuit. There are three ways in which turn-off, or commutation as it is commonly called, can be achieved by: 1. reversing the anode-to-cathode voltage; 2. reducing the anode current below the holding current level; 3. Forcing current in the anode circuit in the reverse direction. When a sinusoidal voltage source is used, turn-off of the SCR occurs automatically at the end of each positive half cycle of applied voltage. When a dc or unidirectional voltage source is used, the anode current must be interrupted or a passive energy storage element is used to attempt to force current through the anode circuit in the reverse direction, which reverses

the

anode

voltage.

Since

the

SCR

is

a

PNPN

junction

semiconductor structure, a minimum time is required for the charges to reverse at the junction after conduction has been interrupted. This time interval is called the turn-off time of the SCR. The turn-off time t off for SCRs is typically 10 to 100 S.

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Experiment Circuit Procedure I (AC Supply): 1. Set the range sector of the analogue ohmmeter to X1. Connect the black lead to terminal A and the red lead to terminal K. Read and record the reading indicated by the pointer. RAK= ______________. Reversing the leads, RAK = _______________ . 2. Connect the black lead of the analogue ohmmeter to terminal A and the red lead to terminal K. Connecting G to A with a wire, read and record the resistance reading indicated by the pointer. RAK = _______________ . The SCR is ________________ (go or no go). Read and record the voltage reading on LV scale as the forward voltage drop between the anode and cathode. VAK(DC) = _______________ V. Remove the analogue multimeter from SCR terminals. 3. Connect 18-VAC power supply to module KL-53003 through the isolation transformer. The 12-V lamp is in RL sockets.

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A.

FOR FIRING DELAY ANGLE FROM 00 TO 900

4. Insert connect plugs in positions 2, 4 and 7. Turning VR2, observe and record the changes of the SCR conduction angle and lamp brightness. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------5. Turn VR2 to get maximum conduction angle. θ=------------- degrees. Using the oscilloscope, measure and record the voltage waveforms of VG in Table 1-1.

Table 1-1 VG waveform (record the peak-to-peak voltage)

B.

FOR FIRING DELAY ANGLE FROM 00 TO 1800

6. Remove connect plug from position 7. Insert connect plugs in positions 5, 6, 8, and 9. Using the oscilloscope, measure the voltage waveform across RL. Turning VR2, observe and record the changes of the SCR conduction angle and lamp brightness. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

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7. Adjust VR2 to get the conduction angle of 90 degrees. Measure and record the voltage waveforms of VG Table 1-2.

Table 1-2 VG waveform (record the peak-to-peak voltage)

8. Remove the connect plug from position 9. Observe and record the changes of VG. VG waveform (record the peak-to-peak voltage)

What made the waveform changes? ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

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Procedure II (DC Supply): 1- Remove the analogue multimeter ad then connect 12 VDC power supplies to module KL-53003. The 12 V-lamp is in RL sockets. 2-Turn VR1 fully CCW and insert connect plugs in position 1, 3, and 7. 3- Turn ON the power and then observe and record the state of RL(lamp). _____________________ using the digital multimeter measure and record the anode and gate voltages. VA= ___________ V, VG= _________________ V. The SCR is operating in ________________ (on or off state). 4- Slowly turning VR1 to the right, observe and record the state of RL (on or off) . When the lamp lights, measure and record the gate voltage. VG = ________________ V. The SCR is operating in ________________________ (on or off) state. 5-Using the digital multimeter, measure and record the anode voltage of the SCR. This voltage is the forward voltage drop (VF) between the anode and cathode of the SCR. VF = ______________________V. 6-Turn VR1 fully CW. Observe and record the states of RL and SCR. ____________________________.Turn VR1 fully CCW. Observe and record the states of RL and SCR. _____________________________________________________________ Explain why there is no change. _________________________________________________________________________ ______________________________________________________ 7-Remove the connect plug from position 1 and then insert it back. Observe and record the states of RL and SCR. _________________________________________________________________________ ______________________________________________________

After Lab Questions: ------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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1-What two things must happen to cause an SCR to be fired (ON state)? ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------2-After an SCR has been fired, what effect does the gate signal have on the SCR? ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

3-Describe the methods used to turn OFF SCRs in dc circuits. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

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Experiment # 2 Unijunction Transistor Characteristics

Student Name: _________________ Student ID: ____________________ Date: _________________________ Score: Reading: Timothy, Modern Industrial Electronics: Chapter 5, Sections 5-1 to 5-3

Objective: 1. Understanding the construction and characteristics of a UJT. 2. Understanding the operation and the two transistor equivalent of a UJT. 3. Measuring the characteristics of a UJT. 4. Constructing and measuring basic UJT application circuits.

Apparatus: -

Power supply unit KL 51001

-

Isolation Transformer KL 58002

-

Module KL 53001

-

Analog multimeter

-

Digital multimeter

-

Oscilloscope

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Summary of theory: The Unijunction transistor (UJT) was originally called a double base diode due to the presence of two base contacts. The interbase resistance RBB is the resistance of the device between terminals B2 and B1 when IE = 0, and can be considered as consisting of the resistors rB1 and rB2 in series. In equation form, R BB  rB1  rB 2 I E 0

The magnitude of rB1 is typically from 5 to 12 k. The resistance is fairly distributed between B1 and B2 when the emitter is open circuited (I E = 0). Due to the position of the emitter is closer to the base 2 contact than the base 1 contact, the magnitude of rB1 is slightly larger than the rB2 value. The resistance rB1 is shown as a variable resistor since its magnitude will vary with emitter current IE. For example, the rB1 values of 2N492 UJT are 4.6 k at IE = 0, 2 k at IE = 1 mA, 150  at IE = 10 mA, and 40  at IE = 50 mA. With IE = 0, the voltage drop on the resistor r B1 is determined by the voltage-divider rule:  r  Vr   B1  V B1 R  BB  B2 B1 I E  0 VrB1  V

B 2 B1 I E  0

The intrinsic standoff ratio of the UJT, , is typically within the range of 0.5 to 0.8.

UJT characteristics: When applied emitter voltage VE is smaller than the peak-point voltage V P, the p-n junction at the emitter is reverse biased and only a small leakage current IEO normally flows in the emitter. The current I Eo usually measured in A, corresponds very closely with the reverse leakage current I Co of the conventional bipolar transistor. This region as indicated in the figure is called the cutoff region.

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When the voltage VE is increased, a voltage is reached where V E is equal to the sum of the forward voltage drop across the p-n junction and the voltage across rB1. This voltage is known as the peak-point voltage V P or firing point voltage. When the applied VE reaches the firing potential V P, the diode will fire and the UJT will conduct from the cutoff region into the negative resistance region. The emitter firing potential is given by VP  VB 2 B1V D

Where the forward voltage drop across the diode V D is typically 0.7 V. as the emitter base1 voltage greater than VP the p-n junction is forward biased so that the holes are injected from the emitter into the silicon n-type material. Since the B1 is negative with respect to the emitter, the electric field is such that most holes move toward the B 1 terminal. An equal number of electrons are injected from B1 to maintain electrical neutrality in the n-type material. The increase in current carried in the silicon material decreases the value of rB1. This causes the fraction of voltage across r B1 to decrease, which causes a further increase of emitter current IE, and a lower resistance of r B1. This region between the peak point voltage VP and the valley point voltage VV on the curve is called negative resistance region. With the characteristic of negative resistance, the UJT is suitable for the application of relaxation oscillator, multivibrator, and timing circuit. At the valley point voltage, the emitter voltage VE increase gradually at currents above I V and then reaches a nearly constant value VEsat. This voltage is called saturation voltage. The region to the right of the valley point is known as the saturation region, where the dynamic resistance is determine d by the slope of I-V curve and is given between 10 and 20 . If the emitter voltage returns to zero, the UJT operating in saturation will be cut off. The emitter resistance of UJT ranges from several hundred ohms to several mega ohms. In cutoff region, the emitter resistance is typically several hundred thousand ohms or several mega ohms. In negative resistance region, the emitter resistance typically

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several thousand ohms and is about several hundred ohms in saturation region.

Testing UJT with ohmmeter: Set the analogue multimeter on 1  K Ω range and connect the red lead to the base 2 of the UJT and black lead to the base 1 a reading between 5 to 12 k should be obtained. Reversing the polarity will be the same reading. This reading represents interbase resistance of the UJT with I E = 0. If the black lead is connected to the emitter and the red lead to the base 1 or base 2, the p-n junction is forward biased by the internal battery and the meter should indicate a low resistance. Thus emitter terminal is located. The resistance of E-B1 is greater than the resistance of E-B2. Thus three terminal of the UJT are identified

Procedure: 1. Connect AC 12 V from power supply unit KL-51001, KL 58002 to module KL 53001.

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Experiment circuit

UJT characteristic measurement 2. Insert connect plug in 1, 4, 6 and 8 positions. Adjust VR1 fully CCW to obtain a minimum resistance. 3. Turn on the power. Observe and record the state of LED. ____________________ The UJT is operating in ________________ region. Using the multimeter, measure and record the voltage across R11. _____________________V. Note: All the measurement should be on DC mode 4. Measure and record the emitter voltage of the UJT with the multimeter (the red lead to E, the black lead to GND). VE = _______________V. ------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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5. Slowly turning the VR1 to the right (CW), observe the change of VE until the voltage reading reaches a peak value and abruptly reduces to a valley value. Record the peak and valley values. The peak value represents the peak point voltage of the UJT and the valley value is the valley point voltage. VP= ___________________ V VV = ___________________V 6. The led is _____________ (on or off). The UJT should operate in ______________ region. 7. Using the multimeter, measure and record the voltage across R11. VR11 = ___________________ V 8. Set the dual trace oscilloscope to X-Y mode. Connect GND of the oscilloscope to the emitter (E) of the UJT, CH1 input to the other terminal of R6, and CH2 (inverted) input to the base 1 (B1) of UJT. Plot the IE-VE curve as on the display of oscilloscope in Plot 2-1.

Plot 2-1 9. Decreasing VR1, observe and record the change of IE-VE curve. _________________________________________________________________________ ____________________________________________________________ ------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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Conclusion:

After Lab Questions: 1-Is a Unijunction transistor a continuously variable device or a switching device? Explain

2-Draw the schematic symbol of a UJT and define its terminals

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Experiment # 3 UJT Oscillator and Timer Circuits

Student Name: _________________ Student ID: ____________________ Date: _________________________ Score: Reading: Timothy, Modern Industrial Electronics: Chapter 5, Sections 5-2 to 5-3 Objective: 1. Understanding the operation of UJT relaxation oscillator circuit . 2. Understanding the operation of UJT timer circuit.

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Apparatus: -

Power supply unit KL 51001

-

Isolation Transformer KL 58002

-

Module KL 53001

-

Digital multimeter

-

Digital Oscilloscope

Summary of theory: The Unijunction transistor (UJT) was originally called a double base diode due to the presence of two base contacts. The interbase resistance RBB is the resistance of the device between terminals B2 and B1 when IE = 0, and can be considered as consisting of the resistors rB1 and rB2 in series. In equation form, R BB  rB1  rB 2 I E 0

The magnitude of rB1 is typically from 5 to 12 k. The resistance is fairly distributed between B1 and B2 when the emitter is open circuited (I E = 0). Due to the position of the emitter is closer to the base 2 contact than the base 1 contact, the magnitude of rB1 is slightly larger than the rB2 value. The resistance rB1 is shown as a variable resistor since its magnitude will vary with emitter current IE. For example, the rB1 values of 2N492 UJT are 4.6 k at IE = 0, 2 k at IE = 1 mA, 150  at IE = 10 mA, and 40  at IE = 50 mA. With IE = 0, the voltage drop on the resistor r B1 is determined by the voltage-divider rule:  r  Vr   B1  V B1 R  BB  B2 B1 I E  0 VrB1  V

B 2 B1 I E  0

The intrinsic standoff ratio of the UJT, , is typically within the range of 0.5 to 0.8. UJT characteristics: ------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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When applied emitter voltage VE is smaller than the peak-point voltage V P, the p-n junction at the emitter is reverse biased and only a small leakage current IEO normally flows in the emitter. The current I Eo usually measured in A, corresponds very closely with the reverse leakage current I Co of the conventional bipolar transistor. This region as indicated in the figure is called the cutoff region. When the voltage VE is increased, a voltage is reached where V E is equal to the sum of the forward voltage drop across the p-n junction and the voltage across rB1. This voltage is known as the peak-point voltage V P or firing point voltage. When the applied VE reaches the firing potential V P, the diode will fire and the UJT will conduct from the cutoff region into the negative resistance region. The emitter firing potential is given by VP  VB 2 B1V D

Where the forward voltage drop across the diode V D is typically 0.7 V. as the emitter base1 voltage greater than VP the p-n junction is forward biased so that the holes are injected from the emitter into the silicon n-type material. Since the B1 is negative with respect to the emitter, the electric field is such that most holes move toward the B 1 terminal. An equal number of electrons are injected from B1 to maintain electrical neutrality in the n-type material. The increase in current carried in the silicon material decreases the value of rB1. This causes the fraction of voltage across r B1 to decrease, which causes a further increase of emitter current IE, and a lower resistance of r B1. This region between the peak point voltage VP and the valley point voltage VV on the curve is called negative resistance region. With the characteristic of negative resistance, the UJT is suitable for the application of relaxation oscillator, multivibrator, and timing circuit. At the valley point voltage, the emitter voltage VE increase gradually at currents above I V and then reaches a nearly constant value VEsat. This voltage is called saturation voltage. The region to the right of the valley point is known as the saturation region, where the dynamic resistance is determine d by the slope of I-V curve and

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is given between 10 and 20 . If the emitter voltage returns to zero, the UJT operating in saturation will be cut off. The emitter resistance of UJT ranges from several hundred ohms to several mega ohms. In cutoff region, the emitter resistance is typically several hundred thousand ohms or several mega ohms. In negative resistance region, the emitter resistance typically several thousand ohms and is about several hundred ohms in saturation region. Prelab From the experimental circuit below find the capacitor charging time T1 and T2 for the following values of C: 1. C=C4=1 µF 2. C=C3=22 µF 3. C=C2=100 µF Example: VR2=minimum, T1=R4*C=510*C VR2=maximum, T2=(R4+VR2)*C=(510+250*103)*C For: C=C4= 1 µF T1=0.00051 seconds, and f1=1960 HZ T2=0.25 seconds, and f2=4 HZ Procedure: 1. Connect AC 110 V input of Power supply unit KL-51001, KL 58002 to AC outlet using AC power cord.

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2. Referring to the experiment circuit, set S1 on Module KL-53001 to OFF. Connect DC 12 V input to +12 V output of power Supply Unit using test leads.

I- OSCILLATOR CIRCUIT 3. Insert connect plugs in position 1, 4, 7,8,11,12, and 14. Turn VR2 fully CCW to get the minimum value of resistance. 4. Switch S1 to ON position. Using the oscilloscope obtain the output waveform (at B1) then record the waveform period T=-------------------------ms Note: If no oscillation occurs, slowly turn VR2 to the right until a visible waveform is present. Draw the voltage waveform at E, determine the parameters of UJT. VV=

V

VP=

V

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6. Turn VR2 fully CW. Observe and record the states of LED and buzzer. LED -------------------------; Buzzer --------------------------7. Justify your result in step 6. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------II- TIMER CIRCUIT 8. Insert the connection plug in position 9 . 9. Turn VR2 all the way to CW direction, then turn S1 ON. Are the LED and the BZ pulsating directly after closing S1 ? -----------------------------10. State whether the above timer is ON-Delay or OFF-Delay -Explain.

--------------------------------------------------------------------------------------------------

Conclusion:

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After Lab Questions: What are the main applications of UJT relaxation oscillators?

Experiment # 4 PUT Characteristics Student Name: _________________ Student ID: ____________________ Date: _________________________

Score: Reading: Timothy, Modern Industrial Electronics: Chapter 5, Section 5-5.

Objective: 1. Understanding the construction and characteristics of a PUT. 2. Measuring the characteristics of a PUT. ------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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Apparatus: -

Power supply unit KL 51001

-

Isolation Transformer KL 58002

-

Module KL 53002

-

Dual-Trace Oscilloscope

-

Analog Multimeter

-

Digital Multimeter

Summary of theory: The programmable Unijunction transistor (PUT) is a four-layer PNPN semiconductor device. The characteristic of the PUT is quite similar to the UJT. An advantage of the PUT over a corresponding UJT is that the important parameter η can be controlled by external components. For further study see pages 206 to 209 (Timothy, Modern Industrial Electronics)

Testing PUT with ohmmeter: An ohmmeter, found on the analog meter, can be used to check the condition of the PUT and to identify the terminals. We use an ohmmeter that the negative of internal battery is internally connected to the + lead (normally the red) and the positive is to the – lead (normally the black). 1. Set the range selector of the multimeter to RX1 range. Connect the red lead to the gate (G) of the PUT and the black lead to the anode (A). A low resistance reading should be indicated. Reversing the polarity will indicate an infinite reading. 2. The resistance between G and K is always infinite despite the polarity. 3. With G open, connect the black lead to the anode (A) and the red lead to the cathode (K) and a low reading is frequently indicated. This is caused by the very high triggering sensitivity of the gate. If the reading is infinite, touching the gate with your fingers will cause the low resistance indicated on the scale. Reversing the polarity, the reading will be infinite. ------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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Calculation: The gate voltage VG of the PUT is determined by the voltage divider network containing VR3 and R9 and written in equation form. VG 

R9 Vs VR3  R9

Adjusting VR3 will change the amount of VG. The anode voltage VA is determined by the voltage-divider network consisting of R4, R5, and VR1 and expressed as: VA 

VR1  R5 VR1  R5  R 4

Vs

The value of VA can be controlled by adjusting VR1.

Procedure: 1. Connect AC 12 V from power supply unit KL-51001, KL 58002 to module KL 53002. Vs

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Experiment circuit A.

PUT characteristic measurement

2. Turn VR1 and VR3 fully CCW. Insert connect plug in positions 1, 4, 6 7, and 10. Set the range selector of multimeter to DC V range. 3. Adjust VR3 to get VG = 3 V (or 2.5V, whichever is stable). 4. The LED is __________________ (ON or OFF). The PUT is operating in _________________ state. Using the multimeter, measure and record the dc voltage across R8. VR8= _________________ V 5. Using the multimeter, measure and record the anode-to-ground voltage. VA= _________________ V 6. Slowly turning VR1 to the right (CW), observe the change of VA until the voltage reading reaches a peak value and abruptly reduces to a valley value. Record the peak and valley values. The peak and valley values represent the peak and valley voltages of the PUT, respectively. VP= _________________ V VV= _________________ V 7. The LED is __________________ (ON or OFF). The PUT is operating in _________________ state. 8. Using the multimeter, measure and record the dc voltage across R8. VR8= _________________ V 9. Turn VR1 to the left (CCW) and adjust VR3 to get VG = 3.5 V by VR3 At the moment LED is __________________ (ON or OFF). Measure VA= _________________ V. The PUT is operating in _________________ state. 10.

Turn VR1 to the right until LED is ON. Measure and record the voltages of VP and VV. VP= _________________ V

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VV= _________________ V 11.

Compare the values of VP and VV in steps 7 and 11. Do they agree? ___________________________________________________ Are the VP and VV values variable? ____________________________________

12. Set the dual-trace oscilloscope to X-Y mode. Connect GND to the anode (A) of the PUT, CH1 input to the other terminal of R6, and CH2 input to the cathode (K). Observe and plot the VAK-IAK curve on the scope display.

Conclusion:

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After Lab Questions: Draw the schematic diagram of PUT and define it’s terminals

Experiment # 5 PUT Characteristics (continue) Student Name: _________________ Student ID: ____________________ Date: _________________________ Score: Reading: Timothy, Modern Industrial Electronics: Chapter 5, Section 5-5.

Objective: 1-Understanding the construction and characteristics of a PUT. 2-Measuring the characteristics of a PUT.

Apparatus: -

Power supply unit KL 51001

-

Isolation Transformer KL 58002

-

Module KL 53002

-

Dual-Trace Oscilloscope

-

Digital Multimeter

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Summary of theory: The programmable Unijunction transistor (PUT) is a four-layer PNPN semiconductor device. The characteristic of the PUT is quite similar to the UJT. An advantage of the PUT over a corresponding UJT is that the important parameter η can be controlled by external components. For further study see pages 206 to 209 (Timothy, Modern Industrial Electronics)

CDS and RTH Replacing R4 by CDS, the light-controlled switch is formed. The CDS is a light –sensitive device and its resistance is inversely proportional to the incident light intensity. The value of VA is determined by the voltage-divider network containing R3, CDS, VR1, and R5. When CDS exposed in a low light level, the resistance of CDS is very high so that VA is too small to turn the PUT on. If a high level reduces the resistance of CDS, VA will increase to a sufficient voltage to fire the PUT and thus the LED is ON. This is a basic streetlight control circuit. In the same manner, replacing R4 by the thermistor RTH, this circuit can be used as a fire alarm circuit. The RTH is a negative temperature coefficient (NTC) thermistor. The resistance of an NTC is inversely proportional to the ambient temperature. In other words, a temperature increase causes the resistance of an NTC thermistor to decrease; a temperature decrease causes the resistance of the thermistor to increase. The operation of this circuit is exactly similar to the CDS light-controlled circuit discussed above.

Calculation: The gate voltage VG of the PUT is determined by the voltage divider network containing VR3 and R9 and written in equation form. VG 

R9 Vs VR3  R9

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Adjusting VR3 will change the amount of VG. The anode voltage VA is determined by the voltage-divider network consisting of R4, R5, and VR1 and expressed as: VA 

VR1  R5 VR1  R5  R 4

Vs

The value of VA can be controlled by adjusting VR1.

Procedure: 1- Connect AC 12 V from power supply unit KL-51001, KL 58002 to module KL 53002.

Experiment circuit

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A. PUT Temperature- Control Circuit 2- Turn VR1 and VR3 fully CCW. 3-Insert connect plug in positions 1, 3, 6, 7, and 10. 4-Adjust VR3 to get VG=3.5 V 5-Slowly turn VR1 and stop at the point where the LED is near ON. Measure and record the voltage of VA. VA=------------------------------------------ V 6- Approach a hot soldering iron to the thermistor RTH. Observe and record the change of VA ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------7-Keep heating the RTH. Observe and record the states of PUT and LED. -----------------------------------------------------------------------------------------8-Remove the soldering iron from RTH . Observe and record the change of the PUT. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------B. PUT light-Control Circuit 9-Remove the connect plug from position 3 and insert it in position 2. Cover the CDS window with your hand. 10-Adjust VR3 to get VG=3.5 V and turn VR1 fully to CW. Observe and record the state of the PUT and LED. -----------------------------------------------------------------------------------------11- Remove your hand from the CDS window to increase sensed light level. Observe and record the states of the PUT and LED. VA= ---------------- V

VG=-----------

V

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

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------------------------------------------------------------------------------------------

Conclusion: After Lab Questions:

In a programmable Unijunction Transistor (PUJT), the main current flow path subsequent to triggering is : a) From G to K b) From G to the A c) From A to K d) From K to A

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Experiment # 6

Automatic Lamp Dimming Circuits Student Name: _________________ Student ID: ____________________ Date: ________________________ Score: Reading: Timothy J.

Maloney, Modern Industrial Electronics Chapter 6-

Section 6-5

Objective: 1. Understanding the operation of TRIAC and SCR phase controls. 2. Understanding the operation of DIAC-TRIAC phase control circuit. 3. Performing an automatic lamp dimming control.

Apparatus: -

Power supply unit KL 51001

-

Isolation Transformer KL 58002

-

Module KL 53007

-

Dual-Trace Oscilloscope

Summary of theory: The TRIAC, like SCR, is often used in an AC circuit to control the power on load. A TRIAC can operate in full-wave phase control circuits while an SCR can operate in half-wave phase control circuits. The most elementary form of full-wave control is the simple DIAC-TRIAC circuit. This circuit is widely used in lamp dimming control and fan speed control circuit. The disadvantage of this circuit is the range of firing angle less than 180 degrees.

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Procedure: 1-Connect 110 VAC power supply from supply Unit KL-51001 -KL-58002 to Module KL-53007. Install the lamp (LP) in the socket on the module. e

Experiment Circuit 2-Insert connect plugs in positions 1, 4, 5, and 12. Turn VR1 completely to CW direction then, turn VR1 gradually to CCW, observe and record the change of lamp brightness. ---------------------------------------------------------------

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3- Turn VR1 to get a maximum brightness (all the way to CCW), then measure and record the voltage waveforms of TRIAC T2 and capacitor C1 in the table below.

4-Remove all connect plugs and insert connect plugs in positions 1, 4, 6, and 11. Turn VR1 completely to CW and then turn it gradually to CCW. ------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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--------------------------------------------------------------

5- Remove all connect plugs and insert connect plugs in positions 2, 4, 8, and 12. Tuning VR1 all the way to CCW, observe the lamp brightness (low or high). -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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-----------------------------------------------------------6- Remove all connect plugs and insert connect plugs in positions 1, 4, 5, and 9 (SCR replaced the Triac). Turn VR1 to get a maximum brightness, Which of the power control circuits has maximum power output (in this step or in step 5 )- Explain ? -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------7- Remove all connect plugs and insert connect plugs in position 1, 3, 6 , and 11 . Expose CDS** to normal light level. Turn VR1 completely to CCW direction . 8- Cover CDS window with your hand. Observe and record the states of lamp, DIAC, and TRIAC- Explain ---------------------------------------------------------------------------------------------------------------------------------------------------------------------9- Remove your hand from CDS window. Observe and record the states of lamp, DIAC, and TRIAC-Explain ---------------------------------------------------------------------------------------------------------------------------------------------------------------------** The CDS is a light-sensitive device and its resistance is inversely proportional to light level. In other words, when light is not present, the resistance is increased. When light is present, the CDS resistance is reduced. The CDS is used to perform the function of automatic lamp dimming control. In normal light level, the trigger potential is set at a low level that can not trigger DIAC to turn on. Thus TRIAC and lamp are off. When the light source is blocked, an increased in CDS resistance causes a sufficient trigger potential to turn the DIAC on. TRIAC is then on and lamp is on.

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Conclusion:

After Lab Questions: Explain the hysteresis (flash-on) effect and the way to eliminate it

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Experiment # 7 Photocoupler and Touch Alarm circuits Student Name: _________________ Student ID: ____________________ Date: _________________________ Score: Objective: 1. Understanding the characteristics of photocoupler. 2. Performing the Photocoupler control circuit. 3. Performing the FET touch alarm circuit. Apparatus: -

Power supply unit KL 51001

-

Isolation Transformer KL 58002

-

Module KL 53008

-

Digital multimeter

Summary of theory: See lecture notes.

Procedure :

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1- Connect 5V and 12 DC supplies from power supply unit KL-51001-KL58002 to Module KL-53008.

Experiment

Circuit

2- Set SW to off position. Insert connect plugs in positions 1, 2, 5, and 7. 3- Which of the LEDs is on? -------------------------------------------Is the relay energized? -----------------------------------------------

4- Using the multimeter, measure and record the voltage at Q1 collector, photocoupler E, Q3 collector , and Q4 collector. VC1=------------------, VE1=----------------------------------VC3=------------------, VC4=----------------------------------5- Set SW to ON position. Is the relay activated? Which of the LEDs is on? ---------------------------------------6- Repeat step 4.

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VC1=------------------, VE1=----------------------------------VC3=------------------, VC4=----------------------------------7- Remove all connect plugs from the Module. Insert connect plugs in position 3, 4, and 6. Does the buzzer sound? ------------------------------------------------------8- Using the multimeter, measure and record the voltage at FET drain, Q3 collector, and Q4 collector. VD2=-------------------------------------------------

VC3=-------------------------, VC4=-----------------------------------

9- Touch the terminal "TOUCH" with your finger. Does the buzzer sound? ------------------------If yes explain why? ---------------------------------------------------------------------------------------Using the multimeter, measure and record the voltage at FET drain, Q3 collector, and Q4 collector. VD=------------------------------------------------VC3=-------------------------, VC4=----------------------------------10-

Remove your finger from the “Touch" terminal. Does the buzzer sound? -------------------If no explain why? ----------------------------------------------------------------------------------------

Conclusion:

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After Lab Questions: Define uses

photocoupler and name some of its industrial

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Experiment # 8

Proportional Temperature Control Student Name: _________________ Student ID: ____________________ Date: _________________________ Score: Reading: Lecture Notes

Objective: 1. Understanding the types and principles of temperature controllers. 2. Performing a proportional temperature controller.

Apparatus: -

Power supply unit KL 51001

-

Isolation Transformer KL 58002

-

Module KL 53008

-

Digital Multimeter

Summary of theory: See section 10-4 to 10-6 16-in EEET 205 text book.

Description of the Experiment Circuit: The figure below shows the experiment circuit. VR2 and thermistors TM1 and TM2 form a resistive bridge. The VR2 is used to control the bridge operating in balance. The VR1 is used to control the voltage applied to bridge. Resistive R1 is to limit the current flowing in bridge when VR1 at low value of resistance. When the output voltage of resistance bridge set to zero, diode D1 and SCR are off so that LED1 lights. If the resistance of TM1 decreases as the temperature increases, the output voltage of the bridge increases and reaches 0.6 V to force D1 to conduct. Hence the SCR turns on and ------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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energizes the relay . LED2 lights to indicate temperature over the setting range. To turn off the SCR, push SW once. Similarly, the resistance of TM2 decreases as the temperature increase. The increase of the bridge output voltage triggers the SCR to conduct. Then LED2 lights on to indicate the temperature too high. Since the output voltage of the bridge is an ac voltage, therefore diode D1 should be used to protect the SCR against a negative pulse applied to the gate.

Experiment Circuit

Procedure: 1- Connect 12V AC supply from power Supply Unit KL-51001-KL-58002 to Module KL-53008. 2- Turn the VR1 fully CCW. Measure and record the voltage across VR2 by using the multimeter. VvR2(ac)= ---------------------V

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3- Using the multimeter, measure the output voltage of resistive bridge to get 0V by turning VR2. At this instant, the resistive bridge operates in balance. 4- Insert connect plug in position 1. Connect 12V DC supply from Power Supply Unit to Module KL-53008. Observe and the states of LEDs and rely. -------------------------------------------------------------------------------If any accident triggering is caused by touching the connect plug with finger, please push switch SW once to initialize the operation. 5-Approach a hot soldering iron to the TM1. Using the multimeter, measure and record the output voltage of the resistive bridge. Vo

=-----------------------------V.

ac

Does the relay operate? Explain--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Which of the LEDs is on? Explain------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------6-Remove the soldering iron from TM1 and cool TM1 for a while. Is the resistive bridge in balance? Why?--------------------------------------------------Is the SCR turned off? ------------------------------------------What is the reason? --------------------------------------------Push SW once. Observe and record the states of SCR and LEDs. ----------------------------------------------------------------------------

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7- Approach the soldering iron to TM2. At the moment LED2 ON Measure and record the output voltage of the resistive bridge Vo ac =-----------------------------V Is the SCR turned on? ------------------------------------------------------8- Remove the soldering iron from TM2 and cool TM2 for a while. Measure and record the output voltage of the resistive bridge. Vo

ac

=------------------V

Is the resistive bridge in balance? --------------------------------------Which of the LEDS is on? -------------------------------------------------What is the state of SCR in? ------------------------------------------------What is the reason? ------------------------------------------9- Push SW once. Observe and record the states of SCR and LEDs. --------------------------------------------------------------------------------------------------------------------------------------------------------

Conclusion:

After Lab Questions: 1-Define thermistor

2-Does thermistor have a positive or negative temperature coefficient of resistance? ------------------------------------------------------------------------------------------------------------------------------Lab Manual, EEET 205: Industrial Electronics (EEET Unit, Hafr Al-Batin Community College)

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Experiment # 9 Motor Starting and Speed Control Student Name: _________________ Student ID: ____________________ Date: _________________________ Score:

Reading: Industrial Electronic Trainer, pp 15-2 to 15-25 Objective: 1. Understanding the types and characteristics of motors. 2. Studying motor speed control circuits 3. Performing Triac motor starting and speed control circuit Apparatus: -

Power supply unit KL 51001

-

Isolation Transformer KL 58002

-

Motor Module KL 58001

-

Module KL-53007

-

Oscilloscope

-

Multimeter

Summary of theory: The universal motor is used in this experiment .This motor is designed to operate on ac or dc voltage. Motor speed can be controlled by adjusting the applied voltage. The universal motor usually operates at very high speeds with good efficiency. The speed will vary considerably with external loading. This motor finds widespread use in many consumer appliances such as sewing machines, vacuum cleaners , mixers, blenders, garden tools, hand drills , and floor polishers.

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Note: The DIAC-TRIAC phase control described in the last experiment is used in this experiment except that the lamp is replaced by universal motor.

Procedure 1. Connect the universal motor on Module KL-58001 to the experiment circuit on Module KL-53007 .

Experiment Circuit

2. Connect 110 VAC supply from power supply Unit KL-51001 to KL53007 module. 3. Turn VR1 fully CW. Insert connect plugs in positions 2, 4, 5, and 8. 4. At this instant, does the motor run ?------------------------

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5. Turning VR1 CCW , observe and record the change of the motor speed. -----------------------------------------------------------------------------------------------6. Turn VR1 to control the motor running at very low speed. Turn the power off and then on. Observe and record the change of the motor speeds. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………….. 7. Set VR1 to get a maximum speed. Using the oscilloscope, measure and record the voltage waveforms at Triac T2 and across C1 below.

8-Turn off the power. Remove the connect plug from position 5 and insert it in position 6. Turn VR1 fully CCW. Record the results in the table below.

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9-Turn off the power. Remove the connect plug from position 6 and insert it in position 7 .Turn VR1 fully CCW. Repeat step 8.

10- Compare the speed in steps, 7, 8, and 9. If they are different explain the reason. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………….. 11-Turn off the power. Remove all connect plugs and then insert them in positions 1, 3, 5, and 8. Turn on the power.

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12- Turn VR1 to set the motor running at low speed when CDS** is exposed to normal light level. Cover CDS window with your hand . Is the motor running? If NO explain why? …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………….. 13- Remove your hand from the CDS window. Is the motor running? If YES explain why? …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… ……………………………………………………………..

14- Measure the current drawn by the motor at no load. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………….. 15- Now, try to prevent the rotor from running and measure the current drawn at the same time. Explain the difference in current reading from step 14. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………….. ** The CDS is a light-sensitive device and its resistance is inversely proportional to light level. In other words, when light is not present, the resistance is increased. When light is present, the CDS resistance is reduced. The CDS is used to perform the function of automatic lamp dimming control. In normal light level, the trigger potential is set at a low level that can not trigger DIAC to turn on . Thus TRIAC and lamp are off. When the light source is blocked , an increased in CDS resistance causes a sufficient trigger potential to turn the DIAC on. TRIAC is then on and lamp is on.

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Conclusion:

After Lab Questions: Explain two methods which can control the speed of a DC motor.

Experiment # 10 Overvoltage and Undervoltage Breaker Student Name: _________________ Student ID: ____________________ Date: _________________________ Score: Reading: Text book “ Modern Industrial Electronics”

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Objective: 1. Understanding the operating principal of overvoltage and undervoltage Relays 2. Performing overvoltage and undervoltage Relay breaker with OP amps Apparatus: -

Power supply unit KL 51001

-

Isolation Transformer KL 58002

-

Module KL- 53009 Multimeter

Description of Experiment Circuit: The figure below shows the overvoltage and undervoltage detector circuit***

SEE SEPARATE HANDOUT

Experiment Circuit Procedure (For Getting A normal operation ) 1. Connect AC 18 V and Ac 12 V supplies from power supply unit KL51001, KL-58002 to Module KL-53009. 2. Turn VR1 and VR2 fully CCW while VR3 fully CW. Insert connect plug in position 1. 3. Measure the input voltage of the bridge rectifier. Adjust VR1 to get a voltage reading of 14 VAC.

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4. Adjust VR3 to get voltage across it approximately equal to 5.2 VDC 5. Adjust VR2 to get voltage across it approximately equal to 5.0 VDC

Conclusion: You have experimented the operation and measurement of OP amp overand undevoltage detection. In normal operation the LEDs are on. If overvoltage condition occurs, LED2 will be off and SCR turn on and cut off the lamp. If undervoltage condition occurs, LED1 will be off and SCR turn on and cut off the lamp.

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