Basic Elec. Engr Basic Elec. Engr. Lab . Lab ECS 204 ECS 204 - - PowerPoint PPT Presentation
Basic Elec. Engr Basic Elec. Engr. Lab . Lab ECS 204 ECS 204 Asst. Prof. Dr. Prapun Suksompong prapun@siit.tu.ac.th Operational amplifier Lab 8 V2I and I2V Converters Inverting Integrator 1 V2I and I2V Converters in out
prapun@siit.tu.ac.th
1
2
L in
L in
V2I Converter I2V Converter
3
R F in
L F in
R in
in
V 1 V
F R
R R
in
V V
F R
R R Non-inverting Amplifier Inverting Amplifier
4
L in
L in
Iout = Vin/R V
These relations hold regardless of the value of RL.
5
Vin, V Iout, mA 1 3 6 10
Iout = Vin/R
6
Iin, mA Vout, V 1 3 6 10
V
Current Source
7
Zero-average input (DC offset = 0)
1
i C i
i t i t v t d C v t R dt v t v v t dt RC
h 2 h h 1 2 T h RC
Area = hT/2
T
i
v t
t
As a Ramp Generator… Sawtooth waveform
8
An input with nonzero mean
(DC offset) can saturate the
1
i C i
i t i t v t d C v t R dt v t v v t dt RC
T
i
v t
t
9
The gain at f = 0 is unbounded. Act like an active low pass filter, passing low
frequency signals while attenuating the high frequencies.
1
C
i
Z V V R V R j C
10
In practical circuit, a large resistor Rp is usually shunted
across the capacitor
Observe that at f = 0, the gain is finite.
R + C + v
v V+ V- X R
/ / 1
C p
p i p
Z R V V R R V R j R C
(w/ DC Gain Control)
11
Output is not triangular. “Virtually triangular” if
R + C + vo
vi V+ V- X Rp
h 1 1 Rp R r h r
1 2 exp
p
r fR C
i
v t
t 1 2
p
R fC 2
p
T R C 1 2
p
C fR
p
R C