Electronic Circuits and electronic circuits, electronic schematics plus an extensive resource for hobbyists, inventors and engineers

DiscoverCircuits.com, has 45,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.
We make every effort to link to original material posted by the designer. 
Please let us if you would like us to link to or post your design.

HOME Schematics Index Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches



Schmitt Trigger Circuits
Schmitt Triggers:  #'s - C      D - Z
 

Last Updated: November 30, 2017 10:28 AM

Circuits Designed by Dave Johnson, P.E. :
CMOS Schmitt Trigger IC Makes VCO -  By changing the supply voltage fed to a classic 4584 Schmitt trigger type oscillator, the oscillator frequency can be changed over a range of 50:1.  A 74HCU04 inverter is used at the output of the 4584 to maintain a constant TTL logic level signal . . . Hobby Circuit designed by David A. Johnson P.E.-March, 2002



Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

12 volt Inverter-Very Basic type -  This circuit will provide a fairly stable "Square Wave" Output Voltage.  Frequency of operation is Mainly determined by the 220 uF Feedback Caps.  Currently about 60 Hz.  Various "off the shelf" transformers can be used. __ Designed by G.L. Chemelec

12 Volt Switching Power Supply -  This is a good Circuit for those persons needing to Boost or drop a voltage.  The Output is High Frequency, but can be Rectified and Filtered to give DC Out.  When Rectifying High Frequencies, You MUST use the Appropriate types of HiGH SPEED Diodes to handle these frequencies.  Normal diodes WiLL OVERHEAT and Burn out.   __ Designed by G.L. Chemelec

120 Volt AC Lamp Dimmer Full Wave SCR -  The full wave phase control circuit below was found in a RCA power circuits book from 1969.  The load is placed in series with the AC line and the four diodes provide a full wave rectified voltage to the anode of a SCR.  Two small signal transistors are connected in a switch configuration so that when the voltage on the 2.2uF capacitor reaches about 8 volts, the transistors will switch on and discharge the capacitor through the SCR gate causing it to begin conducting.  The time delay from the beginning of each half cycle to the point where the SCR switches on is controlled by the 50K resistor which adjusts the time required for the 2uF capacitor to charge to 8 volts.  As the resistance is reduced, the time is reduced and the SCR will conduct earlier during each half cycle which applies a greater average voltage across the load.  With the resistance set to minimum the SCR will trigger when the voltage rises to about 40 volts or 15 degrees into the cycle.   __ Designed by Bill Bowden

13.8 Volt, 20 Ampere linear power supply -  A semi-traditional power supply for communication equipment, using negative-rail regulation with grounded pass transistors in a configuration that gives some unique advantages. __ Designed by Manfred Mornhinweg

A 12 volt Inverter-Very Basic type -  This circuit will provide a fairly stable "Square Wave" Output Voltage.  Frequency of operation is Mainly determined by the 220 uF Feedback Caps.  Currently about 60 Hz.  Various "off the shelf" transformers can be used. __ Designed by G.L. Chemelec

A Good 12 Volt Switching Power Supply -  This is a good Circuit for those persons needing to Boost or drop a voltage.  The Output is High Frequency, but can be Rectified and Filtered to give DC Out.  When Rectifying High Frequencies, You MUST use the Appropriate types of HiGH SPEED Diodes to handle these frequencies.  Normal diodes WiLL OVERHEAT and Burn out.   __ Designed by G.L. Chemelec

A Simple Circuit Inverter -  This circuit will provide a fairly stable "Square Wave" Output Voltage.  Frequency of operation is Mainly determined by the 220 uF Feedback Caps.  Currently about 60 Hz.  Various "off the shelf" transformers can be used. __ Designed by G.L. Chemelec

A Simple Circuit Switching Power Supply -  A Versatile and useful supply to Experiment with, Good for the Beginner to learn.  This is Direct 110 VAC input.   __ Designed by G.L. Chemelec

A Very Basic 12 volt Inverter -  This circuit will provide a fairly stable "Square Wave" Output Voltage.  Frequency of operation is Mainly determined by the 220 uF Feedback Caps.  Currently about 60 Hz.  Various "off the shelf" transformers can be used. __ Designed by G.L. Chemelec

Adaptive Schmitt trigger tames unruly signals -  08/12/13  EDN Design Ideas:  Some biomedical, sensor, and other signals can be almost impossible to derive a clean trigger from.  This circuit could help.  in biomedical instrumentation (for example) , we're sometimes faced with very noisy or badly-behaved signals from which we need to derive information.  in this example, I needed to "square up" a respiration signal, which can exhibit wide variations in amplitude and frequency, along with a wandering baseline.  Presented here is an adaptive "super-Schmitt, " with many adjustable parameters, that did an extremely good job of taming the input signal.   __ Circuit Design by Michael Dunn

Add a Schmitt-trigger function to CPLDs, FPGAs & applications -  10/13/05 EDN Design Ideas:  For slow-slewing signals, hysteresis solves trigger problem __ Circuit Design by Stephan Roche, Santa Rosa, CA

Adjustable HV Output 12 Volt Switching Power Supply -  The Output is Continuously Adjustable from about 20 to 190 Volts.  No Transformer needed, Just a Choke Coil.   __ Designed by G.L. Chemelec

AMI-to-NRZI-Direct-Conversion Tolerates Unequalized Pulse Tails -  03/06/08  EDN Design Ideas:  Using a simple ECL Schmitt trigger, you can convert three-level AMi signals to NRZi.   AMi (alternate-mark inversion) is a three-level—positive, zero, negative—copper-cable transmission code with the useful property of having no dc component for ease of ac coupling using capacitors or line-coupling transformers and a spectral peak at one-half the symbol rate.  The zeros symbols transmit as 0V; the ones symbols transmit at half-unit intervals with alternating-line polarity to maintain the dc balance. __ Circuit Design by Glen Chenier

AN132 - Fidelity Testing for A to D Converters -  Linear Technology AN132 __ Designed by Jim Williams - Oct 1st, 2011

AN17 - Considerations for Successive Approximation A ->D Converters -  Linear Technology AN17 __ Designed by Jim Williams - Dec 1st, 1985

Bipolar Power Supply with LM317t & with LM337t Controllable with Stereo Potentiometer -  introduction LM317T and LM337T are well known and low cost adjustable voltage regulators with current limiting up to around 1.5A and power dissipation up to around 20W.it is useful to have bipolar...__ Electronics Projects for You

Changes Improve Schmitt Trigger -  05/13/99 EDN Design Ideas:  The classical Schmitt trigger circuit that you’ll find in textbooks provide as some noise immunity, such as for the front end of magnetic pickup in position-sensor circuits (Figure 1a].  You adjust the two threshold levelsePDF contains many circuits, scroll to find this one.    __ Circuit Design by Ron Patrick

Circuit forms constant-current SCR -  02/01/01 EDN Design Ideas:  A typical SCR (silicon-controlled rectifier) requires a trigger current, which causes the SCR structure to latch on.  Once the device latches, the current through the SCR is solely a function of external component values.  The SCR has no inherent ability to limit the current flow once it latches on.  Current continues to flow, as long as the current exceeds a minimal value known as the holding current.  The circuit in Figure 1 is similar to an SCR, because it also requires a trigger current to latch into its on state.    __ Circuit Design by Robert Buono, Ringwood, NJ

CMOS Schmitt Trigger IC Makes VCO -  By changing the supply voltage fed to a classic 4584 Schmitt trigger type oscillator, the oscillator frequency can be changed over a range of 50:1.  A 74HCU04 inverter is used at the output of the 4584 to maintain a constant TTL logic level signal. . . Circuit by David Johnson P.E.-December, 2002

Configurable logic gates' Schmitt inputs make versatile Monostables -  05/25/06  EDN Design Ideas:  You can assemble a pulse-generation circuit from a simple Schmitt-input AND gate plus a resistor-capacitor timing network.  However, if you need a logic function that’s not a standard catalog item, you need a Schmitt-input gate or  __ Circuit Design by Glenn Chenier, Allen, TX

Considerations for Successive Approximation A ->D Converters -  Linear Technology AN17 __ Designed by Jim Williams - Dec 1st, 1985

Contact-debouncing algorithm emulates Schmitt trigger -  7-Jul-05 EDN Design Ideas:  Another approach to solving the ubiquitous contact debounce problem __ Circuit Design by Elio Mazzocca, Technical Consultant, Adelaide, South Australia

Convert Solar Powered Light to Flasher -  The circuit converts an off-the-shelf solar powered LED path light from producing a steady state light to one that produces a flash.  This circuit includes a tiny dual Schmitt trigger inverter IC which form the pulse generator and the daylight sensor circuit.  The circuit produces a positive pulse, which feeds the constant current LED driver circuit.. . . Circuit by David Johnson P.E.-March, 2010

Crow Bar #1 -  Depending on the setting or R1, when the voltage exceeds a certain amount, SCR1 triggers, which activates relay RY1 and opens the circuit.  S1 resets the SCR by interrupting power to it.  This is a simple crow-bar circuit for low amperage protection, up to 4 amps at 30V max.  Adjust the SCR for a model that suits your needs.   __ Designed by Tony van Roon  VA3AVR

Crow Bar #2 -  This circuit can be added to any power supply design that does not have additional circuit protection.  When the voltage exceeds either 10V or 30V, depending on the voltage switch setting via the front panel, the zener diode ZD1 conducts and fires the gate of the SCR.  This provides a short-circuit over the output voltage and in turn will blow the AC input fuse of the power supply you wish to protect __ Designed by Tony van Roon  VA3AVR




Schmitt Triggers:  #'s - C      D - Z


HOME Schematics Index Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches


 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |    Privacy Policy


Copyright  January, 1998 - November, 2017     David A. Johnson & Associates.  All Rights reserved. 


 Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.