ATT COMP STUDY GUIDE QUESTIONS AND SOLUTIONS
MARKED A+
✔✔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)
✔✔Tuning Knob - ✔✔Adjusts RF Amplifier
✔✔RF Amplifier - ✔✔Selects and amplifies one of the incoming antenna frequencies
✔✔LO(Local Oscillator) - ✔✔- Provides a frequency to mix with the selected RF signal.
- LO frequency is set 455 kHz above original.
✔✔Mixer - ✔✔Combines the LO and RF frequencies into 4 different variations:
- RF
- LO = RF + 455 kHz
- Sum = LO + RF
- Difference or IF = LO - RF(Will always be 455 kHz)
✔✔IF Amplifier - ✔✔- Amplifies the IF frequency from the mixer.
- Helps filter noise.
✔✔Detector - ✔✔- Usually a made up of diode(rectifier) with some low pass filters(RC
Circuit).
- Detects and extracts the audio intelligence from the IF amplifier and passes the output
audio to the AF Amplifier.
✔✔AF Amplifier - ✔✔- A volume controlled amplifier that raises the power level of the
audio signal to a value sufficient to drive the loudspeaker of the receiver.
, - Comprised of a Pre-Amp, Driver, and Push-Pull Amplifier.
✔✔Pre-amplifier - ✔✔Used to boost the incoming audio signal enough to power the
driver.
✔✔Driver - ✔✔Amplifies audio signal current to drive push-pull amplifier.
✔✔Push-Pull Amplifier - ✔✔Increases the audio signal power to drive the speaker.
✔✔Power Supplies - ✔✔Turn AC to DC.
✔✔Power Supply Pipeline - ✔✔AC in -> Input -> Rectifier -> Filter -> Regulator +
Protection -> DC out
✔✔Input(Power Supply) - ✔✔Steps up or steps down AC voltage.
✔✔Rectifier - ✔✔Changes AC to pulsating DC.
✔✔Filter(Power Supply) - ✔✔Changes pulsating DC to Smooth DC.
✔✔Regulator - ✔✔- Keeps output constant
- Is an optional part of the power supply
✔✔Protection - ✔✔- Limits/disables excess current flow to prevent power supply
damage
- Is an optional part of the power supply
✔✔Rotating Machinery - ✔✔Any machine that has a spinning, or rotating shaft and
uses electricity as the input or output.
✔✔Motors - ✔✔- Have an electrical input and mechanical output.
- Operate on the basis of attraction and repulsion.
✔✔Incremental motor - ✔✔- A motor where the shaft rotates a specific distance for
each input.
-Can be digital or analog
✔✔Stepper Motor - ✔✔A digital incremental motor that uses digital pulses to position
the shaft
✔✔Synchro Motor - ✔✔An analog incremental motor that uses a specific magnitude of
voltage to position the shaft
✔✔Continuous motor - ✔✔- Motor where the shaft spins continuously
MARKED A+
✔✔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)
✔✔Tuning Knob - ✔✔Adjusts RF Amplifier
✔✔RF Amplifier - ✔✔Selects and amplifies one of the incoming antenna frequencies
✔✔LO(Local Oscillator) - ✔✔- Provides a frequency to mix with the selected RF signal.
- LO frequency is set 455 kHz above original.
✔✔Mixer - ✔✔Combines the LO and RF frequencies into 4 different variations:
- RF
- LO = RF + 455 kHz
- Sum = LO + RF
- Difference or IF = LO - RF(Will always be 455 kHz)
✔✔IF Amplifier - ✔✔- Amplifies the IF frequency from the mixer.
- Helps filter noise.
✔✔Detector - ✔✔- Usually a made up of diode(rectifier) with some low pass filters(RC
Circuit).
- Detects and extracts the audio intelligence from the IF amplifier and passes the output
audio to the AF Amplifier.
✔✔AF Amplifier - ✔✔- A volume controlled amplifier that raises the power level of the
audio signal to a value sufficient to drive the loudspeaker of the receiver.
, - Comprised of a Pre-Amp, Driver, and Push-Pull Amplifier.
✔✔Pre-amplifier - ✔✔Used to boost the incoming audio signal enough to power the
driver.
✔✔Driver - ✔✔Amplifies audio signal current to drive push-pull amplifier.
✔✔Push-Pull Amplifier - ✔✔Increases the audio signal power to drive the speaker.
✔✔Power Supplies - ✔✔Turn AC to DC.
✔✔Power Supply Pipeline - ✔✔AC in -> Input -> Rectifier -> Filter -> Regulator +
Protection -> DC out
✔✔Input(Power Supply) - ✔✔Steps up or steps down AC voltage.
✔✔Rectifier - ✔✔Changes AC to pulsating DC.
✔✔Filter(Power Supply) - ✔✔Changes pulsating DC to Smooth DC.
✔✔Regulator - ✔✔- Keeps output constant
- Is an optional part of the power supply
✔✔Protection - ✔✔- Limits/disables excess current flow to prevent power supply
damage
- Is an optional part of the power supply
✔✔Rotating Machinery - ✔✔Any machine that has a spinning, or rotating shaft and
uses electricity as the input or output.
✔✔Motors - ✔✔- Have an electrical input and mechanical output.
- Operate on the basis of attraction and repulsion.
✔✔Incremental motor - ✔✔- A motor where the shaft rotates a specific distance for
each input.
-Can be digital or analog
✔✔Stepper Motor - ✔✔A digital incremental motor that uses digital pulses to position
the shaft
✔✔Synchro Motor - ✔✔An analog incremental motor that uses a specific magnitude of
voltage to position the shaft
✔✔Continuous motor - ✔✔- Motor where the shaft spins continuously
