ECE 2010 Laboratory # 2 J.P.O Rourke

Transcription

1 ECE 2010 Laboratory # 2 J.P.O Rourke Prelab: Simulate all the circuits in this Laboratory. Use the simulated results to fill in all the switch control tables in each part. Your Prelab is due at the beginning of lab and will be checked off by the TA's after the lab starts. Purpose: The objective of this laboratory is to investigate the various ways different types of switches and a relay that maybe used to control lighting and electromechanical devices. Part 1: Setup the circuit below using two switches, a lamp and a relay that will be handed out at the beginning of the lab. These parts must be returned at the end of the lab for use by the next lab section. Wire up the up the circuit on your Kits Breadboard using the precut wires from your wire Kit. The 12 Volt battery will be replaced by a bench Power Supply which is shown below the circuit schematic 3 a 12v 0 J1 Key = B X V J2 Key = A 12v V1 12 V The Ground Symbol is always 0 Volts. b Remote switch control of single 12 volt Lamp.

2 The image of the bench Power Supply shows that it contains three independent Power Supplies with attached lead sets. In this laboratory you only need to use only one of the variable Voltage Supplies labeled "CH1" or "CH2". Note in the image the two push button switches between the two CH1 and CH2 supplies. Make sure both push buttons are in the out position for "Independent" supply operation. Under each Voltage and Current LED Display, are Voltage and Current controls for each of the two variable supplies. Note in the image below the Main power button has been pushed On, but the Output button above, it is still Off (Green LED under button is not on). Under these conditions the Current knobs of both supplies should be turn clockwise from their zero positions to set a limit to the value of current that can flow out the terminals of each supply. In the example below, one supplies current limit is 0.51 amps and the other is 0.20 amps. To use the Power Supply in lab today, connect a set of Red and Black Test Leads to either CH1 or CH2 Red (+) and Black (-) Output Terminals. Since the Output button (upper left-hand corner) is still in the Off position, no power is connected to the Red and Black Leads. To connect power to your circuit, the Output power button needs to be pushed On (LED under button in on(green)). To verify the Power Supply and it s leads are OK the Bench Digital Voltmeter(DVM) will be used to check that there is and output at the Power Supply clip leads. Locate the Bench DVM, Image shown below. There should be a set of leads on the DVM connected to the Red and Black jacks on the face of the meter. Connect the Red lead to the Positive terminal lead of the Power Supply and the Black lead to the Negative terminal lead of the Supply. On the meter, make sure the AC/DC button is not depressed (or out means it is set to DC). Push(depress) the Volts button,

3 next to the AC/DC button and further to the right press the 20 range button since 12 volts is less than 20 volts. Finally, press (turn on) the Power button of the DVM. Now adjust the "B" Voltage control knob until the Voltage meter on the Power Supply reads 12 Volts. If everything is working properly the DVM should be reading something near 12 volts as well, if not adjust the Power Supply Voltage control knob until it does. This method is a check since the Power Supply s analog meter might not be that accurate and why the DVM is being used to check the reading. When done shut off both the Power Supply and DVM s Power / buttons. Repeat this check of the supply for all parts of this lab as standard procedure. Next connect Red clip lead to the Positive Supply part of your circuit and the Black lead to the Negative part of you circuit. If you are unsure about your circuit wiring please ask a TA to check out your circuit since we do realize this is the first time you are using the Proto-Boards and circuit parts. If everything appears OK, turn on the Power Supply s / switch to supply power to your circuit. This should complete your 12 Volt Supply setup to your circuit. If for any reason the light in between the output terminals lights up, turn off the Supply because that indicates the Supply is Current Limiting. The Current Limit light could be on because there is a short in your circuit or your circuit is presenting a load that is greater than the Current Limit setting. If there is no short in your circuit trying turning up the Current Limit a little more. In general, it is possible that the Supply may not be able to deliver the Current your circuit needs and larger Supply maybe necessary.

4 Assuming everything checks out OK, set the circuit switches J1 and J2 according to the table below and record the condition of the lamp for each row setting. Note the appropriate switch position sets the Voltages in the table below. Switch J1 Set to Switch J2 Set to 0 Volts 0 Volts 0 Volts 12 Volts 12 Volts 0 Volts 12 Volts 12 Volts Lamp On Lamp Off Part 2: In this part the circuit schematic is essentially the same except the Power Supply is replaced by and AC(Alternating Current) source. So there is no need to disturb any of the wiring on your Proto- Board, just disconnect the Power Supply leads from your circuit. For this part the DC Supply will be replaced with an AC source called a Function Generator, image shown below.

5 Note, there should be a coaxial lead set connected to the output of the generator(shown above) with Red and Black clips on the output end. Connect the Red clip of this lead to the same place in your circuit that you had the Positive terminal of the DC supply connected. The Black clip then goes to the same place the Negative DC Power Supply went in the circuit. Looking at the front of the generator, top right there are two rows of buttons. On the top row which is the frequency setting, press in the 100 button. This sets the frequency range of the output to a maximum output frequency to around 300 Hz(means,300 cycles per second). On the second row, press the Sine-wave button(the button which looks like a backwards S on its side) it s the button next to the ATT -20dB button. Next, press on the Power button, lower left hand corner. The digital display should light up. Adjust the frequency knob, right under the display for a readout of approximately 60 Hz. Finally, turn the Amplitude(ampl) knob fully clockwise for maximum output. This should be sufficient to light the a 12v 3 0 J1 Key = B X V J2 Key = A 12v V1 12 Vrms 60 Hz 0 The Ground Symbol is always 0 Volts. b Remote switch control of single 12 volt Lamp. Lamp for the appropriate J1, J2 switch settings. If the lamp is very dim press the Square-ware button two buttons to the left of the Sine-wave button, that should make the lamp brighter. The output amplitude of the Square-wave is larger than that of the Sine-wave. As before, set the circuit switches J1 and J2 according to the table below and record the condition of the lamp for each row setting. Note that the actual generator output may less than 12v in some cases which will work alright in this experiment. Switch J1 Switch J2 Lamp On Lamp Off 0 Volts 0 Volts 0 Volts 12 Volts 12 Volts 0 Volts 12 Volts 12 Volts Part 3:

6 Turn the Function Generator Amplitude down to zero(turn knob fully counterclockwise). Now connect another lamp in parallel with the one already in the circuit as shown below. a 12v 3 J1 Key = B 0 1 X1 12 V 2 X2 12 V J2 Key = A 12v V1 12 Vrms 60 Hz 0 The Ground Symbol is always 0 Volts. b Remote switch control of dual 12 volt Lamps. Record the lamp conditions for various J1, J2 switch settings in the following table. Switch J1 Switch J2 Lamp X1 On Lamp X2 On 0 Volts 0 Volts 0 Volts 12 Volts 12 Volts 0 Volts 12 Volts 12 Volts Part 4: In this part replace the two lamps with two LED s connected in parallel in the circuit. Please note that the two diodes are in opposite directions and the Function Generator has been replaced with the DC Power supply. The schematic is shown below. The little flat on the base side of the LED or shorter lead represents the diodes Cathode. The triangle (arrow) on the symbol is the Anode. Current only flows in the direction of the Arrow through the LED when it lights up. Note the Battery(power Supply) is now set to 3.5 volts.

7 Record the LED s operational status for the various switch settings in the table below. Switch J1 Switch J2 LED 1 0 Volts 0 Volts 0 Volts 3.5 Volts 3.5 Volts 0 Volts 3.5 Volts 3.5 Volts LED 1 Part 5: Now remove the DC Power supply and connect the Function Generator back up as before. This make sure the Waveform switch is set to Square-wave for maximum output amplitude.

8 Again, record the LED s operational status for the various switch settings in the table below. Switch J1 Switch J2 LED 1 0 Volts 0 Volts 0 Volts 12 Volts 12 Volts 0 Volts 12 Volts 12 Volts LED 1 Part 6: The last two parts of this experiment will be using a DPDT(double pole, double throw) Relay to control some Lighting and a Motor. In the circuits here the Relay will be used to switch the direction the motor turns. A solid state equivalent of this would be called an H-Bridge. We are using Relay(an electromechanical device) here since it is considerably less expensive than the H-Bridge for our application. The schematic of the simulated circuit shows two SPDT(single pole, double throw) Relays connected in parallel to create a DPDT relay. In the Lab you will be using a DPDT relay so you do not have to create one. The pin outs shown on the simulated Relay match the pin outs of your actual lab bench Relay, so carefully wire it up according to those pin outs. Two SPDT relays connected up to work as a DPDT relay. J2 Key = A J1 on-off micro-switch K 9 K1 R1 600Ω Key = B Select switch 16 K 1 K2 LED1 LED2 + V1 9 V Pin numbers around the Relay apply to the Lab Bench Relay. The images below show what the Micro-switch, Relay and Motor look like that will handed out to you in Lab and need to be returned when you are finished for the next lab section.

9 The image below shows a sample circuit layout for the Relay, Micro-switch and LED s When you have completed the wiring, power up the circuit and record the LED s operational status for the various switch settings in the table below.

10 Switch J1 Key B Switch J2 Key A LED 1 LED 1 Part 7: In this last part of this laboratory, connect the Motor to the same pins that the LED circuit is connected. Leave the LED circuit connected as well. The Motor will be in parallel with the LED circuit. When finished, energize the circuit and fill in the Table noting the LED status and the direction the Motors shaft is turning or not depending on the switch settings. The image below shows the Motor connection, except leave the LED s connected.

11 Two SPDT relays connected up to work as a DPDT relay. J2 Key = A J1 on-off micro-switch K 9 K1 R1 600Ω MOTOR_RATED Key = B Select switch 16 K 1 K2 LED1 LED2 C1 J3 1.0µF + V1 9 V Pin numbers around the Relay apply to the Lab Bench Relay. Switch J1 Key B Switch J2 Key A LED 1 LED 1 Motor Direction CW or CCW or Write up: Answer the following questions using the data obtained in the tables in each part. 1. In parts 1 and 2, can the lamp be turned on and off independently by the two remote switches? 2. In Part 3, where in a home which has upstairs/downstairs, would expect to find this lamp/switch application used? 3. Did you notice any difference in the lamp operation when using a DC or AC Power source? 4. In part 4, the Power source was DC. What does the LED circuit tell you about the current in the common branch in which it is inserted? 5. In part 5, the Power source was AC. Did you note any difference in LED operation when the AC voltage was applied by various switch configurations? 6. In part 6, what function does the J1 switch have in the circuit operation? What function does the Micro-switch J2 have in the circuit operation? What does the LED circuit tell you about the current in the output circuit in which they are inserted? 7. In part 7, the Motor was added to the Part 6 circuit. What function did the micro-switch J2 have on the Motor s operation? What function did the switch J1 have on the Motor s operation?

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