ATT COMP TEST PAPER EXAM QUESTIONS AND
SOLUTIONS MARKED A+
✔✔Magnetic Circuit Breakers - ✔✔Open a circuit by generating a magnetic field when
current flow becomes excessive.
✔✔Multimeter Fun Facts! - ✔✔- Leads are not considered a functional area of the
multimeter.
- When measuring current, don't place/remove leads with the power on.
- Never measure resistance with the power on.
- Best range is always the closest value HIGHER than value to be measured.
✔✔Continuity - ✔✔- The resistance of a wire/connection
- There are two readings for continuity, 0 Ohms(short) or Infinite Ohms(open)
✔✔Junction Diode - ✔✔- Allows current to flow in one direction only
- When forward biased, it acts as a closed switch
- The Triangle is the anode(positive side)
- The Bar/Minus sign is the cathode(negative side)
✔✔Diode Bias Voltage - ✔✔Diodes need a bias voltage to conduct
- Germanium diodes need 0.3 V
- Silicon diodes need 0.7 V
✔✔NPN Transistor Operation - ✔✔- Increasing base bias increases collector current.
- An NPN transistor needs positive base bias to conduct current.
✔✔Saturation - ✔✔Point where an increase in base bias does not increase collector
current.
✔✔Cutoff - ✔✔Point when base bias causes current flow to stop. Happens when EB
Junction is reversed biased.
✔✔Fidelity - ✔✔An amplifiers ability to recreate an input waveform. A class-A amplifier
recreates the entire wave form.
✔✔Transistor Amplifier Classes - ✔✔Class A - High Fidelity, Low Efficiency
Class B - Medium Fidelity, Medium Efficiency
Class AB - Higher Fidelity than B, Lower Efficiency than B.
Class C - Low Fidelity, High Efficiency
✔✔Step-Up Transformers - ✔✔Produce a higher secondary voltage(Es) than primary
voltage(Ep). Secondary has more turns than the primary. Picture has a turn ratio of 1:3.
, ✔✔Transformer Troubleshooting - ✔✔Open primary = No output secondary
Open secondary = No output secondary
Complete short secondary = No output secondary
Partial short primary = Increase secondary voltage
*partial opens do not exist
✔✔Common Emitter - ✔✔- High power gain.
- Assumed Amplification Value(Av) of 10.
- Most commonly used for amplifiers.
- Has a 180 degree phase shift.
✔✔Common Base - ✔✔- High voltage gain(Assumed Av of 10).
- No phase shift.
✔✔Common Collector - ✔✔- High current gain, but low voltage gain(Assumed Av of 1).
- No phase shift.
✔✔Swamping Resistor - ✔✔A component in Transistor Amplifiers that reduces
distortion caused by non-linear current changes.
✔✔Sine Oscillators - ✔✔- Are transistor amplifiers with extra components that sample
the output and return it as the input
- Input and Output are in phase
- Initial output is noise from amp circuit
- Feedback circuit fixes noise
✔✔Crystal Oscillator - ✔✔Use a crystal to determine oscillator frequency. Frequency
should be stated on the crystal(no math necessary).
✔✔LC Oscillator - ✔✔Uses an Inductor and Capacitor to make a tank circuit.
✔✔RC Oscillator - ✔✔Uses resistors and capacitors to determine frequency.
✔✔Hartley Oscillator - ✔✔- An LC oscillator with two Inductors and a ground in
between.
- Changes the DC operating voltage to a sine wave AC output.
✔✔AM Receiver Pipeline - ✔✔RF Input -> Tuner -> IF Amp -> Detector -> AF Amp ->
Audio Output
✔✔Tuner - ✔✔- Coverts the received Radio Frequency(RF) to Intermediate
Frequency(IF)
- Is made up of: tuning knob, RF Amplifier, Mixer, and Local Oscillator(LO)
SOLUTIONS MARKED A+
✔✔Magnetic Circuit Breakers - ✔✔Open a circuit by generating a magnetic field when
current flow becomes excessive.
✔✔Multimeter Fun Facts! - ✔✔- Leads are not considered a functional area of the
multimeter.
- When measuring current, don't place/remove leads with the power on.
- Never measure resistance with the power on.
- Best range is always the closest value HIGHER than value to be measured.
✔✔Continuity - ✔✔- The resistance of a wire/connection
- There are two readings for continuity, 0 Ohms(short) or Infinite Ohms(open)
✔✔Junction Diode - ✔✔- Allows current to flow in one direction only
- When forward biased, it acts as a closed switch
- The Triangle is the anode(positive side)
- The Bar/Minus sign is the cathode(negative side)
✔✔Diode Bias Voltage - ✔✔Diodes need a bias voltage to conduct
- Germanium diodes need 0.3 V
- Silicon diodes need 0.7 V
✔✔NPN Transistor Operation - ✔✔- Increasing base bias increases collector current.
- An NPN transistor needs positive base bias to conduct current.
✔✔Saturation - ✔✔Point where an increase in base bias does not increase collector
current.
✔✔Cutoff - ✔✔Point when base bias causes current flow to stop. Happens when EB
Junction is reversed biased.
✔✔Fidelity - ✔✔An amplifiers ability to recreate an input waveform. A class-A amplifier
recreates the entire wave form.
✔✔Transistor Amplifier Classes - ✔✔Class A - High Fidelity, Low Efficiency
Class B - Medium Fidelity, Medium Efficiency
Class AB - Higher Fidelity than B, Lower Efficiency than B.
Class C - Low Fidelity, High Efficiency
✔✔Step-Up Transformers - ✔✔Produce a higher secondary voltage(Es) than primary
voltage(Ep). Secondary has more turns than the primary. Picture has a turn ratio of 1:3.
, ✔✔Transformer Troubleshooting - ✔✔Open primary = No output secondary
Open secondary = No output secondary
Complete short secondary = No output secondary
Partial short primary = Increase secondary voltage
*partial opens do not exist
✔✔Common Emitter - ✔✔- High power gain.
- Assumed Amplification Value(Av) of 10.
- Most commonly used for amplifiers.
- Has a 180 degree phase shift.
✔✔Common Base - ✔✔- High voltage gain(Assumed Av of 10).
- No phase shift.
✔✔Common Collector - ✔✔- High current gain, but low voltage gain(Assumed Av of 1).
- No phase shift.
✔✔Swamping Resistor - ✔✔A component in Transistor Amplifiers that reduces
distortion caused by non-linear current changes.
✔✔Sine Oscillators - ✔✔- Are transistor amplifiers with extra components that sample
the output and return it as the input
- Input and Output are in phase
- Initial output is noise from amp circuit
- Feedback circuit fixes noise
✔✔Crystal Oscillator - ✔✔Use a crystal to determine oscillator frequency. Frequency
should be stated on the crystal(no math necessary).
✔✔LC Oscillator - ✔✔Uses an Inductor and Capacitor to make a tank circuit.
✔✔RC Oscillator - ✔✔Uses resistors and capacitors to determine frequency.
✔✔Hartley Oscillator - ✔✔- An LC oscillator with two Inductors and a ground in
between.
- Changes the DC operating voltage to a sine wave AC output.
✔✔AM Receiver Pipeline - ✔✔RF Input -> Tuner -> IF Amp -> Detector -> AF Amp ->
Audio Output
✔✔Tuner - ✔✔- Coverts the received Radio Frequency(RF) to Intermediate
Frequency(IF)
- Is made up of: tuning knob, RF Amplifier, Mixer, and Local Oscillator(LO)
