28-03-2012, 03:11 PM
Analog Electronics
Lect01-2P-C analog electronics.pdf (Size: 310.9 KB / Downloads: 51)
Linear Amplifiers (1)
Multiply amplitude of a signal by a constant scalar quantity
xo(t) = A xi(t)
Non-scalar or
non-uniform
amplification
is called
distortion
Linear Amplifiers (2)
• Symbol for a single-ended
input linear voltage amplifier.
• Ideally provides linear
voltage gain regardless of
the amplitude of the input
signal
• Real amplifiers have power
supplies that limit the
amplitude of the output
• If input is too large, output
clamps
Real Transfer Characteristics
• Each circle represents
a different DC
component for the
input and output
signals – called an
operating point
• Location of operating
point has an effect on
• input signal range
• amplifier gain magnitude
• amount of distortion
Signal Convention (1)
• DC magnitudes in uppercase symbol and
subscript
– Example: ID, VD
• Ac signal quantities in lowercase symbol &
subscript
– Example: id(t), vd(t)
• Total DC + ac signal quantities in lowercase
symbol, uppercase subscript
– Example: iD(t), vD (t)
Superposition
• If the amplifier is linear, superposition can be
applied. Each component can be determined
seperately.
• Determine the DC magnitude of the output using
DC model (i.e capacitors are open circuited,
inductors are short circuited)
– Example: IO, VO
• Determine the ac signal component of the output
using the ac model (i.e., DC sources are killed and
capacitors are short circuited, inductors are open
circuited) as