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Absolute value circuit delivers high bandwidth:
05/15/03 EDN-Design Ideas / Most absolute-value
circuits have limited bandwidth and high
component count, and they require several
matched resistors. The circuit in Figure 1 uses
three fewer components than most absolute-value
circuits require, and only two of the resistors
must have 1% tolerance to obtain 1% accuracy.
This circuit's output voltage is an accurate
representation of the absolute value of the
input signal,.... |
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Absolute value comparator touts accuracy, size:
03/07/2002 EDN - Design Ideas / 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 more
positive than VREF, the output of IC2A goes low.
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Design low duty cycle timer circuits:
08/22/2002 EDN - Design Ideas / 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.. |
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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 you avoid
the bother of stocking and replacing fusible
links. The circu... |
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Expanded scale indicator revisited:
08/08/2002 EDN - Design Ideas / 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-�A dc meter and a
series resistor |
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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"no- missing-codes"specification
grows proportionately. To fully guarantee no
missing codes for a 16-bit ADC requires testing
all 2 16-1 possible output...
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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'... |
