ATT Quiz Exam Questions with Verified
Answers
Pulsating DC - Answer-Current that varies in amplitude but does not reverse polarity
`Not alt. Current because polarity remains the same.
Protection. - Answer-Optional section in an scr power supply. Prevents damage to
power supply from excess current flow.
AC to DC - Answer-Diode reflectors
Power Supply - Answer-AC to DC
Half Wave Diode Reflector - Answer-AC to DC
(VDC=VPeak of secondary x .318)
Full Wave Diode Rectifier - Answer-AC to DC
VAVG= [VPP/2] x .636
If center tapped:
VAVG= [VPP/4] x .636
Diodes preform reflection
180° out of phase
Bridge Diode Rectifier - Answer-Only conducts if forward biased.
(VAVG= VPEAK x .636)
Output: pulsating DC
Half Wave rectifier freq - Answer-Ripple req: same as input freq
Full wave rectifier freq - Answer-Ripple freq: twice input freq
With half VPEAK output
Bridge rectifier freq - Answer-Ripple freq: twice input freq
Output: twice the voltage of a full wave
Applied voltage is taken across the full potential of the transformer - Answer-Advantage
of a Bridge vs Full wave
Voltage regulators purpose - Answer-Adjust voltage to maintain Eout at a constant level
Zener diode normal operation - Answer-Fwd biased: low ohms
Rev biased: high ohms
Zener diode - Answer-Series voltage regulator
, Efficiency of a full wave vs half wave - Answer-Full wave is more efficient because an
output is developed for entire wave form
Purpose of a series volt regulator - Answer-Maintain constant output voltages to a load
series volt regulator - Answer-Load current increases, r1 square root = er square root
Eout increases, DC increases (OR current of load square rooted) - Answer-In a Parallel
volt regulator...
rev bias Zener Diode - Answer-Rev bias when anode (+) is more - than cathode (-)
In a zener reg.. Q1 Fwd bias increases when ___ ___ ___. - Answer-load current
increases
Q1 maintains output voltage level - Answer-In a variable volt regulator...
input V increases, Q1s voltage increases - Answer-In a variable volt regulator...
reverse biasing an SCR with a multimeter - Answer-Put meters negative port on anode
Current is applied by jumper cables from anode to gate - Answer-How to check an SCR
gate
Polarized Outlet - Answer-Ensures hot wire is not common to chassis and isolates the
circuit from AC line
Voltage doubler - Answer-When in need of high volt and low current
Voltage doubler purpose - Answer-Change AC voltage into DC with a substantial
increase on magnitude
Half wave voltage doubler - Answer-RMS x 1.414 =PEAK
C2 >/ peak in x2
Ripple increases and output sq rt - Answer-If load is added to a voltage doubler
Voltage multiplier vs current vs output - Answer-The higher the multiplication factor, the
worse the ripple , the lower the output, higher the component rating must be.
Lower the multiplier the higher the current
IC Regulator 7812 - Answer-Max current: 1.5 A
Regulates to 12 volts
RL sould never drop below 8 ohms
Answers
Pulsating DC - Answer-Current that varies in amplitude but does not reverse polarity
`Not alt. Current because polarity remains the same.
Protection. - Answer-Optional section in an scr power supply. Prevents damage to
power supply from excess current flow.
AC to DC - Answer-Diode reflectors
Power Supply - Answer-AC to DC
Half Wave Diode Reflector - Answer-AC to DC
(VDC=VPeak of secondary x .318)
Full Wave Diode Rectifier - Answer-AC to DC
VAVG= [VPP/2] x .636
If center tapped:
VAVG= [VPP/4] x .636
Diodes preform reflection
180° out of phase
Bridge Diode Rectifier - Answer-Only conducts if forward biased.
(VAVG= VPEAK x .636)
Output: pulsating DC
Half Wave rectifier freq - Answer-Ripple req: same as input freq
Full wave rectifier freq - Answer-Ripple freq: twice input freq
With half VPEAK output
Bridge rectifier freq - Answer-Ripple freq: twice input freq
Output: twice the voltage of a full wave
Applied voltage is taken across the full potential of the transformer - Answer-Advantage
of a Bridge vs Full wave
Voltage regulators purpose - Answer-Adjust voltage to maintain Eout at a constant level
Zener diode normal operation - Answer-Fwd biased: low ohms
Rev biased: high ohms
Zener diode - Answer-Series voltage regulator
, Efficiency of a full wave vs half wave - Answer-Full wave is more efficient because an
output is developed for entire wave form
Purpose of a series volt regulator - Answer-Maintain constant output voltages to a load
series volt regulator - Answer-Load current increases, r1 square root = er square root
Eout increases, DC increases (OR current of load square rooted) - Answer-In a Parallel
volt regulator...
rev bias Zener Diode - Answer-Rev bias when anode (+) is more - than cathode (-)
In a zener reg.. Q1 Fwd bias increases when ___ ___ ___. - Answer-load current
increases
Q1 maintains output voltage level - Answer-In a variable volt regulator...
input V increases, Q1s voltage increases - Answer-In a variable volt regulator...
reverse biasing an SCR with a multimeter - Answer-Put meters negative port on anode
Current is applied by jumper cables from anode to gate - Answer-How to check an SCR
gate
Polarized Outlet - Answer-Ensures hot wire is not common to chassis and isolates the
circuit from AC line
Voltage doubler - Answer-When in need of high volt and low current
Voltage doubler purpose - Answer-Change AC voltage into DC with a substantial
increase on magnitude
Half wave voltage doubler - Answer-RMS x 1.414 =PEAK
C2 >/ peak in x2
Ripple increases and output sq rt - Answer-If load is added to a voltage doubler
Voltage multiplier vs current vs output - Answer-The higher the multiplication factor, the
worse the ripple , the lower the output, higher the component rating must be.
Lower the multiplier the higher the current
IC Regulator 7812 - Answer-Max current: 1.5 A
Regulates to 12 volts
RL sould never drop below 8 ohms
