Year 2 D6 Flashcards
Rectifier
changes alternating current to direct current
Half-wave rectifier cct
connect a diode in series with an AC load
the PIV rating for diodes used in biphase full wave rectification must be
more than twice the peak voltage appearing across the load
ripple frequency
the number of output pulses DC
60 Hz half wave rectification makes 60 Hz out
60 Hz full wave rectifcation makes 120 Hz out
Capacitor filters are not normally used
where large load currents and good voltage regulation are required
when using a capacitor sized for max filtering action
the average DC voltage across the load is equal to the peak AC voltage
PIV rating for diode used as rectifiers
2 time E max
DC meters indicate average values of E and I
for power calculations in rectified DC cct. effective or rms value of sine-wave E and I
Power formula for Full-wave cct
P = (Emax x Imax)/2
Power formula for half-wave cct
P = (Emax x Imax)/4
Form factor = Erms/Eav .707/.637
Half wave .707/.318
is a ratio for full and half-wave rectifier cct.
compares the AC input to the average DC output
to operate an NPN transistor
emitter must be negative
base must be positive
collector must be positive
to operate a PNP transistor
emitter must be positive
base must be negative
collector must be negative
in semiconductor symbols the arrow
always points from P to N type material
transistors ratings
Small signal (low Hz)
Power (low Hz)
High Hz
Switching
