Download PRACTICAL ASSESSMENT

ASSESSMENT REPORT
FOR
SINGAL STAGE AMPLIFIER HIGH-FEED BACK
Name: Rameshkumar Kandasamy
Date: 28/06/ 2010
Unit: UEENEEEH013B
Faulty Description: SINGLE-STAGE AMPLIPIER HIGH-FEED BACK
Describe the scope of the work to be undertaken:
1. Figure out the sequences in relation to connecting transistor, and then connect resistors with the
transistor after that connect power supply two voltages separately to the transistor each to supply
10v.Connect a function generator to the transistor to provide electrical wave forms connect an
oscilloscope to the ground, V out resistor of the transistor each to test wave forms. Finally change a
feedback resistor into a high-feed back resistive value.
(This task should be done before you commenced any work on the computer. From the nature of the
fault try to establish what should be done in what steps.)
List the tools, equipment and testing devices required to complete the task
1. Choose Two D.C power supplies source.
2. Digital multimeter to read the values of the components. it more easy to use it and read values
compared to an analogue one.
3. Function generator in order to offer sine wave in the circuit.
4. Used Oscilloscope to print out the signal of V out on a screen.
(Describe the selection criteria or process for each tool, equipment or testing device)
List all materials and components required to complete the task.
1. Transistor BC 547 NPN SIGNAL Z 1300 to provide an amplified V out on the screen.
2. Varies Resistors (1kohm, 2kohm, 4kohm, 8kohm, 1kohm) as given on the diagram.
3. Wires (to make connections to all parts)
(Describe the selection criteria or process for each material or component)
Describe steps, or methodology required to identify the fault.
1. We connected all different valued resistors to a transistor according to the diagram.
2. Applied the formula (summing amplify formula) in order to check out a faulty outcome.
To find out any faulty transistors and resistors is being in the circuit.
Describe the steps, tasks or modifications required to undertake to solve the fault. Include any
measured values and/or calculations to support your findings.
Modification:
changing low value resistor into high value
1. We took out the feedback resistor (1k)
2. Inserted high-valued feedback (470k ohm) into that resistor which has been taken out previously.
3. Findings: Vout voltage went higher, which was 20V ( Vout increased)
Describe the re-assembly and testing process. Test the functionality of the device against the
requirements. Describe in detail the testing process undertaken and record the data/values
1. We tested the output voltage in the circuit with a multimeter.
2. We found out 20 volts output from the transistor. Which is increased Vout after mounting a
High value resistor into the circuit.
List the manufacturer’s manuals, datasheets or any other documentation required to complete
this task. List the information sought in particular document.
Summing Amplifier (diagram and formula)
Identify if there were any risks involved in completion of this task.
Risk;
1. There was burns happened in the fingers, Amplifier Explosion these incident happened by
mistakenly, changing a too low resistor could cause fingers to be burnt and Passing too much current
into a transistor because sudden transistor burst.
If so, describe the procedures followed to lessen, if not eliminate, each of the identified risks.
1. To avoid those risks, check thoroughly values of resistors, before mounting them in the circuit.
2. And also confirming applicable maximum voltage on the transistor prior to setting it up.
List any unexpected situations that occurred during this practical task and how they were
addressed (if applicable).
Not applicable for this project.
ASSESSMENT REPORT
FOR
SINGAL STAGE AMPLIFIER SHORTED FEEDBACK
Fault Description: Signal stage amplifier shorted feedback.
Describe the scope of the work to be undertaken:
1. We did trouble shooting test at the faulty parts in the circuit with a multimeter after
Confirming faulty parts we replaced the parts with new ones.
2. Then did testing procedures.
(This task should be done before you commenced any work on the computer. From the nature of the
fault try to establish what should be done in what steps.)
List the tools, equipment and testing devices required to complete the task
1. Digital multimeter to read the values of the components. It is much more easier to read values
compared to an analogue one.
(Describe the selection criteria or process for each tool, equipment or testing device)
List all materials and components required to complete the task.
1. A 100 ohm 5W resistor to replace shorted feedback resistor.
(Describe the selection criteria or process for each material or component)
Describe steps, or methodology required to identify the fault.
We checked the input feedback resistor. Then we read the values of collector- emitter section of the
transistor. The reason for checking ohm values with a multimeter to ascertain if it’s faulty one or not.
Describe the steps, tasks or modifications required to undertake to solve the fault. Include any
measured values and/or calculations to support your findings.
While making the testing producer we read 0 ohm from the shorted feedback resistor. Then we
took out the faulty one lifting connection pins from the board. Mounted a new resistor into the board.
.
Describe the re-assembly and testing process. Test the functionality of the device against the
requirements. Describe in detail the testing process undertaken and record the data/values
We measured the transistor’s collector-emitter voltage was 7.8 V With a multimeter which was
not a shorted (0 ohm) one and also we tested an feedback resistor of the transistor with a multimeter
with a Probe we read 100 ohm (not shorted 0 ohm) on that.
Then finally we confirmed amplifiers increased voltage from the amplifier’s output which was
20 Volt.
List the manufacturer’s manuals, datasheets or any other documentation required to complete
this task. List the information sought in particular document.
1. We referred to BC 547 transistor reference sheet on this task.
Identify if there were any risks involved in completion of this task.
Risks:
1. Finger Burns and amplifier explosion. because of mistakenly, changing a too low resistor could
cause fingers to be burnt and passing too much current into a transistor made a sudden burst.
If so, describe the procedures followed to lessen, if not eliminate, each of the identified risks.
To avoid the above mentioned risks, check thoroughly values of resistors, before mounting them in the
circuit and also confirming applicable maximum voltage on the transistor prior to setting them up.
List any unexpected situations that occurred during this practical task and how they were
addressed (if applicable).
Nothing unexpected situation happened in this task.
ASSESSMENT REPORT
FOR
SINGAL STAGE AMPLIFIER SHORTED INPUT
Faulty Description: SINGLE-STAGE AMPLIPIER SHORTED INPUT
Describe the scope of the work to be undertaken:
We supplied 10 volts into the amplifier then we read the values of the components by using a
multimeter to find out what was the fault in the circuit. After confirming faulty parts, finally we replaced
those bad parts with new ones.
(This task should be done before you commenced any work on the computer. From the nature of the
fault try to establish what should be done in what steps.)
List the tools, equipment and testing devices required to complete the task
1. Two D.C power supplies to provide volts into amplifier.
2. A Digital multimeter to check the values of the components. It is much easier to read values
compared to an analogue.
(Describe the selection criteria or process for each tool, equipment or testing device)
List all materials and components required to complete the task.
1. A 100 ohm resistor to replace shorted input resistor with the new one.
(Describe the selection criteria or process for each material or component)
Describe steps, or methodology required to identify the fault.
1. We supplied 10 volts into the amplifier. Then we checked resistor voltage with a multimeter.
2. We checked resistors values on the amplifier to see if it’s shorted one or not in the circuit.
Describe the steps, tasks or modifications required to undertake to solve the fault. Include any
measured values and/or calculations to support your findings.
We read 0v (shorted resistor) one of the feedback resistors then we took out the shorted one from the
board and mounted a new resistor inserting pins on the board.
.
Describe the re-assembly and testing process. Test the functionality of the device against the
requirements. Describe in detail the testing process undertaken and record the data/values
We supplied two each of 10 volts into the amplifier’s inputs. We ascertained output voltage.
With a multimeter and also we tested feed back resistor value with a multimeter it was 100 ohm (not 0
ohm) on that.
List the manufacturer’s manuals, datasheets or any other documentation required to complete
this task. List the information sought in particular document.
1. We referred to BC 547 transistor reference sheets on this task.
Identify if there were any risks involved in completion of this task.
Risks:
Finger burns and amplifier explosion happened by mistakenly, changing a too low resistor could cause
fingers to be burnt and let passing too much current into a transistor cause transistor burst.
If so, describe the procedures followed to lessen, if not eliminate, each of the identified risks.
To avoid above risks, check thoroughly values of resistors, before mounting them into the circuit and
also confirming applicable maximum voltage on the transistor prior to setting them up.
List any unexpected situations that occurred during this practical task and how they were
addressed (if applicable).
Nothing unexpected happened on this task.