analog-to-digital converter and multi-vibrators
DESCRIPTION
Analog-to-Digital Converter and Multi-vibrators. Simple Digital to Analog Converter. .111 corresponds to 7/8 7/8 of 5 is 4.375. Simple Digital to Analog Converter. .100 corresponds to 1/2 1/2 of 5 is 2.5. Analog-to-Digital. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/1.jpg)
PHY 202 (Blum) 1
Analog-to-Digital Converter and Multi-vibrators
![Page 2: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/2.jpg)
PHY 202 (Blum) 2
Simple Digital to Analog Converter
V15 V
J1
Key = AJ2
Key = B
J3
Key = CR11.0k
R22.0k
R34.02k
R44.02k
U1DC 10M4.377 V
+
-
.111 corresponds to 7/8
7/8 of 5 is 4.375
![Page 3: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/3.jpg)
PHY 202 (Blum) 3
Simple Digital to Analog Converter
V15 V
J1
Key = AJ2
Key = B
J3
Key = CR11.0k
R22.0k
R34.02k
R44.02k
U1DC 10M2.503 V
+
-
.100 corresponds to 1/2
1/2 of 5 is 2.5
![Page 4: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/4.jpg)
PHY 202 (Blum) 4
Analog-to-Digital• We have seen a simple digital-to-analog converter,
now we consider the reverse process• For this purpose we introduce a new circuit
element — the comparator • We have seen last semester a digital comparator, a
logic circuit that determined whether the input word A is larger than the input word B
• Now we look at an analog comparator, it determines whether voltage A is larger than voltage B
![Page 5: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/5.jpg)
PHY 202 (Blum) 5
![Page 6: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/6.jpg)
PHY 202 (Blum) 6
Comparator (analog)
U1
COMPARATOR_VIRTUALV13.1 V V2
3 V
R11.0k
U2DC 10M4.651 V
+
-
+ Input higher than – input, output is high
![Page 7: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/7.jpg)
PHY 202 (Blum) 7
Comparator (analog)U1
COMPARATOR_VIRTUALV12.9 V V2
3 V
R11.0k
U2DC 10M0.000 V
+
-
+ Input lower than – input, output is low
![Page 8: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/8.jpg)
PHY 202 (Blum) 8
1-bit analog-digital converter
V15 V
R11.0k
R21.0k
V22.4 V
U1
COMPARATOR_VIRTUAL
X1
2.5 V
Reference Voltage
Input voltage
Input voltage is less than half of reference voltage, result is low.
![Page 9: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/9.jpg)
PHY 202 (Blum) 9
1-bit analog-digital converter
Reference Voltage
Input voltage
Input voltage is more than half of reference voltage, result is high.
V15 V
R11.0k
R21.0k
V22.6 V
U1
COMPARATOR_VIRTUAL
X1
2.5 V
![Page 10: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/10.jpg)
PHY 202 (Blum) 10
Toward a 2-bit analog-digital converter
V15 V
R11.0k
R21.0k
V24 V
U1
COMPARATOR_VIRTUAL
X1
2.5 VGreater than 3/4
R41.0k
R51.0k
U2
COMPARATOR_VIRTUALU3
COMPARATOR_VIRTUAL
X2
2.5 VGreater than 1/2
X3
2.5 VGreater than 1/4
![Page 11: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/11.jpg)
PHY 202 (Blum) 11
Toward a 2-bit analog-digital converter
V15 V
R11.0k
R21.0k
V22.6 V
U1
COMPARATOR_VIRTUAL
X1
2.5 VGreater than 3/4
R41.0k
R51.0k
U2
COMPARATOR_VIRTUALU3
COMPARATOR_VIRTUAL
X2
2.5 VGreater than 1/2
X3
2.5 VGreater than 1/4
![Page 12: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/12.jpg)
PHY 202 (Blum) 12
Toward a 2-bit analog-digital converter
V15 V
R11.0k
R21.0k
V22.2 V
U1
COMPARATOR_VIRTUAL
X1
2.5 VGreater than 3/4
R41.0k
R51.0k
U2
COMPARATOR_VIRTUALU3
COMPARATOR_VIRTUAL
X2
2.5 VGreater than 1/2
X3
2.5 VGreater than 1/4
![Page 13: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/13.jpg)
PHY 202 (Blum) 13
Toward a 2-bit analog-digital converter
V15 V
R11.0k
R21.0k
V21.1 V
U1
COMPARATOR_VIRTUAL
X1
2.5 VGreater than 3/4
R41.0k
R51.0k
U2
COMPARATOR_VIRTUALU3
COMPARATOR_VIRTUAL
X2
2.5 VGreater than 1/2
X3
2.5 VGreater than 1/4
![Page 14: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/14.jpg)
Finish this truth table
>3/4 Comparator
>1/2 Comparator
>1/4 Comparator
½’s place ¼’s place
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
PHY 202 (Blum) 14
Doesn’t occur
![Page 15: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/15.jpg)
PHY 202 (Blum) 15
Integrated circuit version
Warning: may need to flip switch back and forth.
![Page 16: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/16.jpg)
PHY 202 (Blum) 16
3.7 / 5 (in Scientific Mode)
![Page 17: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/17.jpg)
PHY 202 (Blum) 17
* 2 x^y 8 =
![Page 18: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/18.jpg)
PHY 202 (Blum) 18
Binary Mode
![Page 19: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/19.jpg)
PHY 202 (Blum) 19
Compare
![Page 20: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/20.jpg)
PHY 202 (Blum) 20
Scientific Mode
![Page 21: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/21.jpg)
PHY 202 (Blum) 21
Multi-vibrators
http://www.ee.ed.ac.uk/~kap/Hard/555/node1.html
![Page 22: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/22.jpg)
PHY 202 (Blum) 22
Multi-vibrator
• A multi-vibrator is an electronic circuit that can exist in a number of “states” (voltage and/or current outputs).
• A flip-flop is a bi-stable multi-vibrator, bi-stable means it has two stable states.
• A state is stable if it is robust against the fluctuations (noise) that are always occurring.
![Page 23: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/23.jpg)
PHY 202 (Blum) 23
Mono-stable multi-vibrator• A mono-stable multi-vibrator has one stable
output (usually zero). • It also has an unstable state. Certain input will
put the circuit into its unstable state, which lasts for a set length of time before returning to the stable state.– Unstable states are still robust to noise but do not last
indefinitely long.
• In wave terminology, this provides one with a single pulse.
![Page 24: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/24.jpg)
PHY 202 (Blum) 24
Pulse
STABLE UNSTABLESTABLE
![Page 25: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/25.jpg)
PHY 202 (Blum) 25
One shots• One purpose of a mono-stable multi-vibrator is to
output a signal of a specified duration. • The input (trigger) may be short (or unknown) in
duration, but the output pulse has a predictable duration (can be controlled by the time constant of an RC circuit). = RC– The time constant and duration are not equal but
are proportional.
• Such a circuit is called a “one shot.”
![Page 26: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/26.jpg)
PHY 202 (Blum) 26
Shapers
• Another purpose of mono-stable multi-vibrators is to “shape” input signals.
• Recall in digital circuits we want signals to be clearly high or low; a mono-stable multi-vibrator can take signals which are not of this form and create signals which are.
![Page 27: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/27.jpg)
PHY 202 (Blum) 27
Schmitt trigger
![Page 28: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/28.jpg)
PHY 202 (Blum) 28
Schmitt trigger
• If the voltage is above a certain value (the upper trip point) and rising, the output is high.
• If the voltage is below another value (the lower trip point) and falling, the output is low.
• Otherwise, it remains whatever it was.
![Page 29: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/29.jpg)
PHY 202 (Blum) 29
Schmitt trigger
The upper trip point
The lower trip point
Above the upper trip and going up
Below the lower trip and going down
![Page 30: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/30.jpg)
PHY 202 (Blum) 30
A-stable multi-vibrator
• In an a-stable multi-vibrator, there are typically two states, neither of which is stable.
• The circuit repeatedly flips back and forth between the states.
![Page 31: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/31.jpg)
PHY 202 (Blum) 31
A-stable multi-vibrator
R11.0kR2
10.0k
V15 V
C1
2.0uF
C2
2.0uF
J1
Key = Space
Q1
BJT_NPN_VIRTUAL
Q2
BJT_NPN_VIRTUAL
R31.0k R4
10.0k
XSC1
A B
G
T
![Page 32: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/32.jpg)
PHY 202 (Blum) 32
A-stable Multi-vibrator
• Assume a state where the transistor on left is ON and transistor on right is OFF and the capacitor on the left has no charge.
• Since the left transistor is on (hard) it is not dropping much voltage, therefore “all” the voltage is being dropped by the resistors
• The capacitor on the left begins to charge through the 10K resistor on the right
![Page 33: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/33.jpg)
A-stable Multi-vibrator
PHY 202 (Blum) 33
![Page 34: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/34.jpg)
A-stable Multi-vibrator Oscilloscope
PHY 202 (Blum) 34
![Page 35: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/35.jpg)
PHY 202 (Blum) 35
A-stable
ON OFF
low
high
Charge building up
![Page 36: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/36.jpg)
PHY 202 (Blum) 36
A-stable
• Charge builds up on the left capacitor, “pulling-up” the voltage presented to the base of the transistor on the right.
• When the base reaches about 0.7v the transistor on the right turns on.
• Current now starts to flow through the 1K resistor on the far right, thus dropping the voltage level at the collector.
• That low voltage makes its way to the base of the transistor on the left turning it off.
• The cycle repeats itself.
![Page 37: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/37.jpg)
PHY 202 (Blum) 37
A-stable
ON
low
Turns off
![Page 38: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/38.jpg)
PHY 202 (Blum) 38
Duty cycle
• In a square wave (e.g. a computer’s clock), the wave is characterized by its frequency, its amplitude and its duty cycle.
• The duty cycle is the percent of time that the signal is high.
• Duty cycle = thigh/(thigh+tlow)*100%
![Page 39: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/39.jpg)
PHY 202 (Blum) 39
Duty cycle example: thigh = 1.407 ms
![Page 40: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/40.jpg)
PHY 202 (Blum) 40
Duty cycle example: thigh + tlow = 2.111 msDuty cycle = (1.407/2.111) = 66.65%
![Page 41: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/41.jpg)
PHY 202 (Blum) 41
555 Timer
• A similar circuit uses the 555 chip (Integrated circuit)
• The resistors and capacitors are external to the chip so that the period and duty cycle of the circuit can be controlled.
![Page 42: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/42.jpg)
PHY 202 (Blum) 42
555
![Page 43: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/43.jpg)
PHY 202 (Blum) 43
555 as Monostable multivibrator
![Page 44: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/44.jpg)
PHY 202 (Blum) 44
555 as Astable Multivibrator
![Page 45: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/45.jpg)
PHY 202 (Blum) 45
555 Timer (WorkBench version)
U1
LM555CM
GND
1
DI S7
OUT 3RST4
VCC
8
THR6
CON5
TRI2
V15 V
C11.0uF
C210nF
R11.0k
R21.0k
XSC1
A B
G
T
![Page 46: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/46.jpg)
PHY 202 (Blum) 46
Crystals
• The very high frequency square wave used for the CPU clocks are not generated in the manner described on the previous slides.
• The high frequency signal is supplied by crystals subjected to an electric field.
![Page 47: Analog-to-Digital Converter and Multi-vibrators](https://reader036.vdocument.in/reader036/viewer/2022062310/56815c39550346895dca2e2b/html5/thumbnails/47.jpg)
PHY 202 (Blum) 47
References
• http://www.ee.ed.ac.uk/~kap/Hard/555/node2.html#modes
• http://en.wikipedia.org/wiki/555_timer_IC
• http://www.kpsec.freeuk.com/555timer.htm