6.002 Demo# 21
Schmitt Trigger
(Load set up demo#21.set)
Agarwal Fall 00
Lecture 21
Purpose:
Demonstrates a Schmitt Trigger
Steps:
Part 1: Show slew rate of op-amp without feedback
Output
Note: Delay on scope should be set at 610
Time base = 1 usec
Part 2: A slow sweep of input shows hysteresis on output.
Cite as: Anant Agarwal and Jeffrey Lang, course materials for 6.002 Circuits and Electronics,
Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of
Technology. Downloaded on [DD Month YYYY].
Part 3: Use Schmitt Trigger to clean up noisy sine wave.
Input noise sq. wave
Part 4: Place feedback around Schmitt trigger and add a capacitor to create triangle and square waves.
R'
100 K Pot
7
CH4 = 1v/Div
1K
+
C'
Vert CH2 =>5v/Dv
-741
22
+
.5 uF
Clean Output
100 K
100 K
- 15 V
10 K
1K
SYM
Cite as: Anant Agarwal and Jeffrey Lang, course materials for 6.002 Circuits and Electronics,
Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of
Technology. Downloaded on [DD Month YYYY].
6.002/6.071 Op-Amp
Used old demo #5
7633
50 Ohm
Op-Amp Ckts 2 Board
6.071/6.002 4-D-E Board
Left
7A26
7B53A
22
7
Right
22
Trig Out
Gain
Home Made #1
(22) H. Made #2
Home Made #2
(20) #1
H.P. Dual Supply
(5) #1
Horiz. CH4
Square Wave
Vert CH2
Cite as: Anant Agarwal and Jeffrey Lang, course materials for 6.002 Circuits and Electronics,
Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of
Technology. Downloaded on [DD Month YYYY].
Part 1:
CH4 2v/Dv
-
80 Hz Square Wave
+
50
741
CH2 >5v/Dv
50
Output
Note: Delay on scope should be set at 610
Time base = 1 usec
Equipment:
Fader System and (2) cameras
Small monitor
HP Dynamic Signal Analyzer
(2) RC Circuit of 1 K, .01 uF
(kept in 6.002 demo drawer)
(2) BNC-Clip, BNC Tees
Amplifier and speaker
Scope Settings:
Vert CH1 = 2v/Div, Display CHOP
Vert CH2 = 2v/Div
Vert Mode = Left
Vert CH3 & CH4 = .5v/Div
Horiz. CH2 = .2v/Div Display CH2
Trig Amplifier
Mode = Norm
Coupling = DC
Source = Int
Sweep= 10 ms/Div
Cite as: Anant Agarwal and Jeffrey Lang, course materials for 6.002 Circuits and Electronics,
Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of
Technology. Downloaded on [DD Month YYYY].
Part 2:
Horiz. CH4 = 2v/Dv
1K
7
+
HYS
741
22
1K
10 K
- 15 V
1K
SYM
Cite as: Anant Agarwal and Jeffrey Lang, course materials for 6.002 Circuits and Electronics,
Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of
Technology. Downloaded on [DD Month YYYY].
Part 3:
20
10 K
Sine wave 1200 Hz
5
Horiz. CH4 = 2v/Dv
1K
-
22
7
1K
--
+
Sq.Wave 200 Hz
+
22
741
+
Clean Output
Summer
HYS
10 K
10 K
- 15 V
1K
SYM
Note Sync Lock
Part 4:
Horiz. CH4 = 2v/Dv
R'
100 K Pot
7
1K
+
C'
Vert CH2 =>5v/Dv
--
CH4 = 1v/Div
741
22
+
.5 uF
Clean Output
100 K
100 K
- 15 V
10 K
1K
SYM
R ' C ' = External components
Cite as: Anant Agarwal and Jeffrey Lang, course materials for 6.002 Circuits and Electronics,
Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of
Technology. Downloaded on [DD Month YYYY].