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Zero Cross Detector Circuits Last Updated on:
Monday, October 03, 2011 06:08 PM
Circuits Designed by Dave
Johnson, P.E.:
40KHz Ultrasound Receiver
A X100 transistor amplifier is followed by a zero cross detector circuit, using a
voltage comparator. The output is a TTL logic signal, corresponding to the
received 40KHz signal. (added 7/06)
LINE POWERED
60Hz CLOCK GENERATOR
This circuit is connected to the 120vac power line and transfers 60Hz clock pulses
to a logic circuit. The optoisolator used provides 5000 volts of isolation between
the power line and the logic side of the circuit.
WIDE BAND
ZERO CROSS DETECTOR
This circuit was designed to convert a low amplitude 40KHz signal into a clean
square wave signal. It will work with inputs as small as 5mv peak to peak or
as large as 3 volts peak to peak. The input frequency can range from a few
kilohertz to about 150KHz.
Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
40kHz Ultrasound Receiver - A X100 transistor amplifier is
followed by a zero cross detector circuit, using a voltage comparator.
The output is a TTL logic signal, corresponding to the received 40KHz
signal.... [Designed by David A. Johnson]
Circuit yields accurate absolute values - 5-Jul-01 Issue of EDN
The circuit in Figure 1 delivers the absolute value of the input signal with
an accuracy better than 10 ppm of the full-scale range. The circuit has low
zero-crossing error. You can use it as an asynchronous demodulator, as a
source for logarithmic amplifiers, or simply as a demonstration of the
wonders of feedback.... [Design Idea by Marco Pisani, Istituto di Metrologia
G Colonnetti, Turin, Italy]
Line Powered 60hz Clock Generator - This circuit is connected to
the 120vac power line and transfers 60Hz clock pulses to a logic circuit.
The optoisolatorused provides 5000 volts of isolation between the power line
and the logic side of the circuit.... [Designed by David A. Johnson]
Paralleling decreases autozero-amplifier
noise by a factor of two - 7-Jun-07 Issue of EDN By simply paralleling
four amplifiers of a quad auto-zero amplifier, you can decrease output noise by a
factor of two.... [Design Idea by Marián Štofka, Slovak University of Technology,
Bratislava, Slovakia]
Sample-and-hold amplifier holds the difference of two inputs 07/24/08 EDN
Design Ideas....You can fulfill a requirement for sampling the difference of two
signals in two classic ways. You can subtract the two input signals with an
instrumentation amplifier whose output connects to an input of a classic
sample-and-hold amplifier ….PDF has several circuits, scroll to find this design….
[Design Idea by Marián Štofka, Slovak University of Technology, Bratislava, Slovakia]
Time-tag impulses with zero-crossing circuit - 24-Jan-02 Issue of EDN
A "constant-fraction discriminator" usually performs the time-tagging of impulsive
events, which have a peaking time of the signal amplitude. The implementation of this
technique requires a delay in the input signal of approximately the same amount as the
signal's rise time. You can attain this delay by using a coaxial cable of an
appropriate length.... [Design Idea by Elio Rossi, Itesre-CNR, Bologna, Italy]
Wide Band Zero Cross Detector - This circuit was designed to convert a low
amplitude 40KHz signal into a clean square wave signal. It will work with inputs
as small as 5mv peak to peak or as large as 3 volts peak to peak. The input
frequency can range from a few kilohertz to about 150KHz. …. [Designed by David A.
Johnson]
Zero crossing AC switch oscillator - The circuit shown will switch on and
off a resistive or inductive load up to 800VA with the possibility to adjust both the
on and off period. Switching takes place during the zero crossing of the sine wave.
The switch on point is around the zero crossing but....(added 9/07
