ATT COMP MAIN EXAMINATION SET QUESTIONS AND
SOLUTIONS MARKED A+
✔✔three characteristics needed for sine wave - ✔✔frequency, period, wavelength
✔✔wavelength - ✔✔actual distance between beginning and end of cycle (lamda)
✔✔induction - ✔✔generation of AC I by changing magnetic field (flux)
when a conductor passes through a magnetic field
✔✔to induce a current you need... - ✔✔A conductor, a magnetic field, and relative
motion
✔✔Peak value
Peak-to-peak
Avg value
RMS - ✔✔highest positive or negative V obtained
doubling peak value
sum of all angles in 180 degrees 0.637*Vp
describes V of sine wave 0.707 *Vp
✔✔AC vs DC effectiveness - ✔✔AC is only 70.7% as effective as DC
✔✔Oscilloscope - ✔✔Electronic test equipment, measure amplitude, Period, and wave
shape. From these measurements you can find frequency, phase, pulse, etc.
✔✔RMS calculation - ✔✔find Vp (=Vpp/2) then Vrms (=0.707*Vp) then current (I=V/R or
Vrms=IR) then Vp (=Vrms/0.707)
✔✔Inductor - ✔✔component that has the ability to concentrate a magnetic field
wire wrapped and a core
Induced opposes the voltage applied
✔✔When switch opened with an inductor in ckt - ✔✔the Va is gone but the Vind makes
the current continue to produce a current through ckt until it decreases and then current
stops
✔✔Classifications of inductors(schematic) - ✔✔air core (normal), iron core(normal with
two parallel lines), and variable(normal with variable arrow through it, used in Qs and
receivers).
✔✔Inductance - ✔✔basic unit is Henry (H, big so usually mH), ability of conductor to
induce(generate) V when cut by mag F.
, ✔✔Factors determining L - ✔✔turns of wire, distance between windings, cross sectional
area of core, and permeability(ease of material being magnetized) of core
✔✔Capacitor - ✔✔-component that can store an electrical charge
two parallel plates separated by a dielectric
-at first acts like a short but then as it charges becomes an open
-pass AC but block DC
✔✔Classifications of Cs (schematic symbol) - ✔✔non polarized (normal), electrolytic
(normal but has a positive on one side), and variable (normal with variable arrow
through it).
✔✔Capacitance - ✔✔the ability of a conductor to store energy in the form of electrically
separated charges (Farad F large but picoF normal)
✔✔Amount of capacitance factors - ✔✔plate size (bigger increases C), distance b/w
plates (closer increases C), and dielectric material(compared values to air).
✔✔Transistors - ✔✔control a large I with a small I
✔✔Emitter - ✔✔heavily doped so it emits larger # of I carriers inside semi C material
✔✔Base - ✔✔Very thin and lightly doped, allows most I carriers to pass between E to C
✔✔Collector - ✔✔moderately doped, largest area, dissipate heat
✔✔Two types of signals applied to Qs? - ✔✔Input and bias
✔✔quiescent - ✔✔inactive; at rest, but ready to op
✔✔Power supplies does what - ✔✔convert AC P to DC P
✔✔Power supply cantons five sections what are they? - ✔✔Input, Rectifier, Filter,
Regulator and Protection
✔✔P supply: Input. - ✔✔consist of a P transformer
✔✔P supply: Rectifier. - ✔✔Converts AC to pulsating DC
✔✔P supply: Filter section. - ✔✔changes pulsating DC to smooth DC
✔✔P supply: Regulator. - ✔✔maintains output V at a constant level despite changes in I
load
SOLUTIONS MARKED A+
✔✔three characteristics needed for sine wave - ✔✔frequency, period, wavelength
✔✔wavelength - ✔✔actual distance between beginning and end of cycle (lamda)
✔✔induction - ✔✔generation of AC I by changing magnetic field (flux)
when a conductor passes through a magnetic field
✔✔to induce a current you need... - ✔✔A conductor, a magnetic field, and relative
motion
✔✔Peak value
Peak-to-peak
Avg value
RMS - ✔✔highest positive or negative V obtained
doubling peak value
sum of all angles in 180 degrees 0.637*Vp
describes V of sine wave 0.707 *Vp
✔✔AC vs DC effectiveness - ✔✔AC is only 70.7% as effective as DC
✔✔Oscilloscope - ✔✔Electronic test equipment, measure amplitude, Period, and wave
shape. From these measurements you can find frequency, phase, pulse, etc.
✔✔RMS calculation - ✔✔find Vp (=Vpp/2) then Vrms (=0.707*Vp) then current (I=V/R or
Vrms=IR) then Vp (=Vrms/0.707)
✔✔Inductor - ✔✔component that has the ability to concentrate a magnetic field
wire wrapped and a core
Induced opposes the voltage applied
✔✔When switch opened with an inductor in ckt - ✔✔the Va is gone but the Vind makes
the current continue to produce a current through ckt until it decreases and then current
stops
✔✔Classifications of inductors(schematic) - ✔✔air core (normal), iron core(normal with
two parallel lines), and variable(normal with variable arrow through it, used in Qs and
receivers).
✔✔Inductance - ✔✔basic unit is Henry (H, big so usually mH), ability of conductor to
induce(generate) V when cut by mag F.
, ✔✔Factors determining L - ✔✔turns of wire, distance between windings, cross sectional
area of core, and permeability(ease of material being magnetized) of core
✔✔Capacitor - ✔✔-component that can store an electrical charge
two parallel plates separated by a dielectric
-at first acts like a short but then as it charges becomes an open
-pass AC but block DC
✔✔Classifications of Cs (schematic symbol) - ✔✔non polarized (normal), electrolytic
(normal but has a positive on one side), and variable (normal with variable arrow
through it).
✔✔Capacitance - ✔✔the ability of a conductor to store energy in the form of electrically
separated charges (Farad F large but picoF normal)
✔✔Amount of capacitance factors - ✔✔plate size (bigger increases C), distance b/w
plates (closer increases C), and dielectric material(compared values to air).
✔✔Transistors - ✔✔control a large I with a small I
✔✔Emitter - ✔✔heavily doped so it emits larger # of I carriers inside semi C material
✔✔Base - ✔✔Very thin and lightly doped, allows most I carriers to pass between E to C
✔✔Collector - ✔✔moderately doped, largest area, dissipate heat
✔✔Two types of signals applied to Qs? - ✔✔Input and bias
✔✔quiescent - ✔✔inactive; at rest, but ready to op
✔✔Power supplies does what - ✔✔convert AC P to DC P
✔✔Power supply cantons five sections what are they? - ✔✔Input, Rectifier, Filter,
Regulator and Protection
✔✔P supply: Input. - ✔✔consist of a P transformer
✔✔P supply: Rectifier. - ✔✔Converts AC to pulsating DC
✔✔P supply: Filter section. - ✔✔changes pulsating DC to smooth DC
✔✔P supply: Regulator. - ✔✔maintains output V at a constant level despite changes in I
load
