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Absolute-value comparator touts accuracy, size - 7-Mar-02
Issue of EDN A typical window comparator uses two comparators
and a single op amp to determine whether a voltage is inside or
outside a boundary region. Figure 1 shows a typical
implementation. IC1 is an inverting op amp with a gain of –1.
VREF and –VREF create the window limits. When VIN becomes
positive than VREF, the output of IC2A goes low..... [Design
Idea by Teno Cipri, Engineering Expressions Consulting,
Sunnyvale, CA] |
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Add hysteresis to a voltage comparator - 4-Mar-10 Issue of
EDN Positive feedback is a typical technique for distributing
hysteresis around a comparator, provided that you have a
resistive path between the comparator's output and the
non-inverting input. Positive feedback forms two threshold
voltages that have (or assume] fixed values. In addition, they
depend on the saturation values of the comparator's output
stage..... [Design Idea by Luca Bruno, ITIS Hensemberger Monza,
Lissone, Italy] |
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An IC Voltage Comparator for High Impedance Circuitry -
National Semiconductor Application Note |
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AN-41: Precision IC Comparator Runs from +5V Logic Supply -
National Semiconductor Application Note |
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AN-87: Comparing the High Speed Comparators - National
Semiconductor Application Note |
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Applications of the LM392 Comparator Opamp Ic - National
Semiconductor Application Note 04-Nov-1995 |
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Circuit Techniques for Avoiding Oscillations in Comparator
Applications - National Semiconductor Application Note |
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Comparator provides stable hysteresis - 03/18/99 EDN-Design
Ideas Unless a voltage-comparator circuit is sampling an
extremely clean signal, the comparator always requires some
hysteresis. Traditional comparator circuits ….PDF contains
multiple circuits, scroll to find this circuit..... [Design Idea
by Fernando Garcia, Lucent Technologies, Brownsville, TX] |
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Comparator uses Signal Dependent Hysteresis - 03/26/98 EDN-Design
Ideas..... A project posed the challenge of replacing existing
analog potentiometers (used to set brightness and contrast
levels]in video monitors with digitally controlled
potentiometers. The different brands and models of monitors
presented widely varying voltages across the potentiometers.....
[Design Idea by P Krehlik and L Sliwczynski, University of
Mining and Metallurgy, Krakow, Poland] |
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Comparators Form 3 to 5 Volt or 5 to 3 Volt Translator/Tranceiver
- 09/02/96 EDN-Design Ideas.....In many recent systems, you
often need to interface 3V signals with higher voltages within
the system. In some cases, it's necessary to interconnect 3 and
5V open-collector transceivers.Figure 1 shows one example, in
which multiple multidrop communications devices interconnect. In
systems where no control lines are available for interfacing,
the..... EDN is migrating links. This link is not verified.
Google the "title" EDN for new link. |
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Comparing the High Speed Comparators - National
Semiconductor Application Note |
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Design an efficient reset circuit - 1-May-03 Issue of EDN
When you work with microprocessors, you must ensure that when
the power-supply voltage fluctuates to the minimum permissible
level, VL, that the processor's ALU continues to operate
normally. Also, when you switch on the power supply, the ALU
must operate normally when the supply voltage equals or exceeds
a certain high level, VH..... [Design Idea by Guillermo Bosque,
Asesoría e Integracion de Tecnologías, Urduliz, Spain] |
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Design low-duty-cycle timer circuits - 22-Aug-02 Issue of
EDN Designing astable circuits using the industry-standard 555
timer is a straightforward process when duty cycles are 50% or
greater. However, you must overcome the many pitfalls of
low-duty-cycle circuits to arrive at a desired result. Using
only ideal components eases the design, but the components
themselves are hard to obtain..... [Design Idea by Phil Rogers,
Texas Instruments Inc, Rockwall, TX] |
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Dual comparators stabilize proximity detector - 02/16/98
EDN-Design Ideas.....In the proximity detector of Figure 1, a
4-in.-sq piece of copper-plated pc board serves as an antenna
that forms one plate of a capacitor. An approaching (grounded]
person serves as the other plate, producing a
capacitance.....File has many circuits, scroll to find this
one..... [Design Idea by Arthur Harrison, US Army Research
Laboratory, Adelphi, MD, and Joseph Stern, Maxim Integrated
Products, Sunnyvale, CA] |
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Electronic fuse emulates fast- or slow-blow fuses -
11/09/00 EDN-Design Ideas.....The electronic-fuse circuit in
Figure 1 combines the properties of a current transducer and a
solid-state relay to disconnect low power at preset levels.Using
this circuit lets….PDF contains multiple circuits, scroll to
find the one of interest..... [Design Idea by John A Hasse,
Colorado State University, Fort Collins, CO] |
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Expanded-scale indicator revisited - 8-Aug-02 Issue of EDN
The visualization aid that a previous Design Idea describes
allows only the expansion of the upper end of the scale
(Reference 1]. But what can you do if, according to your project
requirements, you need to expand the middle region of the scale?
Figure 1a illustrates the challenge. A voltmeter comprises a
100-µA dc meter and a series resistor..... [Design Idea by Abel
Raynus, Armatron International Inc, Melrose, MA] |
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Fast Voltage Comparators with Low Input Current - National
Semiconductor Application Notes,28-Jun-1996 |
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LB-12: Linear Brief 12 an IC Voltage Comparator for High
Impedance Circuitry - National Semiconductor Application
Note |
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LB-32: Linear Brief 32 MicroVolt Comparator - National
Semiconductor Application Note |
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LB-39: Linear Brief 39 Circuit Techniques for Avoiding
Oscillations in Comparator Applications - National
Semiconductor Application Note |
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LB-6: Fast Voltage Comparators with Low Input Current -
National Semiconductor Application Note |
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Light Sensor With Hysteresis - It is quite a simple circuit
but rather more effective than the one using the 741. It uses a
simple comparator LM311 as the master piece. This comparator is
powered from a +12V DC supply and does not require negative
supply to work efficiently. The feedback given to the comparator
provides some hysteresis and the potentiometer allows to adjust
the sensitivity of the detector for darkness. I am quite sure
you could inverse R1 and R2 positions to inverse the action of
the detector but I haven't tried it! …. [By Frank Rivard] |
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LM139/LM239/LM339 a Quad of Independently Functioning
Comparators - National Semiconductor Application Note
24-Feb-1999 |
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Low Voltage Alarm - NE555 Low Voltage Battery Disconnect
Circuit… [design by Arron Cake] |
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MicroVolt Comparator - National Semiconductor Application
Notes first published 28-Jun-1996 |
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Missing codes Tester checks 16 Bit ADC in 7 sec - 06/10/99
EDN-Design Ideas.....As the resolution of ADCs increases from 12
to 16 bits and higher, the difficulty in testing
the"nomissing-codes"specification grows proportionately. To
fully guarantee no missing codes for a 16-bit ADC requires
testing all 2 16-1 possible output..... EDN is migrating links.
This link is not verified. Search the "title" + EDN for new
link. |
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Missing Pulse Detector Basic - This circuit is a one-shot
that is continually retriggered by incoming pulses…. [Tony van
Roon's circuit] |
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One-shot provides frequency discrimination - 1-May-03 Issue
of EDN You use a frequency discriminator to compare one signal
frequency with another one. A functional feature, retriggering,
of a monostable, one-shot 74xx123 multivibrator can yield
frequency discrimination. Figure 1 shows a frequency
discriminator that determines the relation of input-pulse
frequency to a reference frequency..... [Design Idea by Victor
Aksenenka, CSRI Elektropribor, St Petersburg, Russia] |
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Precision IC Comparator Runs from Plus 5 Volt Logic Supply
- National Semiconductor Application Note 04-Nov-1995 |
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Schottky diodes improve comparator’s transient response -
21-Jan-10 Issue of EDN Two Schottky barrier diodes clamp error
voltages, cut output glitches..... [Design Idea by Marián Stofka,
Slovak University of Technology, Bratislava, Slovakia] |
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Synchronized Window Comparator Eliminates Error - 05/11/95
EDN-Design Ideas.....Precision A/D converters need a window
comparator. The window comparator in Fig 1a is synchronized to
the clock signal. This synchronization eliminates errors that
could arise when the input signal crosses the high or low
threshold (Fig 1b]unsynchronized to clock. In operation,
comparator IC1A sets flip-flop IC2..... [Design Idea by Sergey
Velichko, Consultant, Bosie, ID] |
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Two Buttons Provide Safe Start - 07/06/00 EDN-Design
Ideas.....The circuit in Figure 1 provides a safety interlock
that checks the actuation of two pushbuttons before enabling a
relay. When you push both buttons, the circuit actuates the
relay. At that point, you can release one of the switches
without the relay'..... [Design Idea by Vincent Himpe, Alcatel
Microelectronics, Desselgem, BelgiumVincent Himpe, Alcatel
Microelectronics, Desselgem, Belgium] |
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Voltage Comaparator and Q Multiplier make a stable Sine Wave
Oscillator - It is a known fact that sinusoidal oscillators
must rely on the action of some amplitude limiting mechanism in
order to achieve good frequency and amplitude stabilities.
Likewise, accurate loop-gain control and high-Q tuned circuits
are required for the attainment of low-distortion output levels. |
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Voltage Comparator - This experiment only requires a single
operational amplifier. The model 1458 and 353 are both "dual"
op-amp units, with two complete amplifier circuits housed in the
same 8-pin DIP package. |
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Voltage Comparator Forms Pulse Demodulator - 11/19/98 EDN-Design
Ideas.....To process low-level ultrasound or radio-range pulses,
you need a signal-conditioning amplifier followed by a pulse
demodulator to translate the signals to dc pulses.
Traditionally, you would use a diode-demodulator configuration
(for example, the circuit in Figure 1a] with one stage of a
single-supply op amp.....scroll to find this one..... [Design
Idea by [Abel Raynus, Armatron International, Melrose, MA] |
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Voltage Comparator Switch - This circuit will provide an
indication whenever the input voltage differs from two defined
limits, V1 and V2. The supply voltage, Vcc must be higher than
the highest input voltage by at least 2 volts. One application
here is to monitor a 12V car battery. |
