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Signal Generator Circuits

Signal Generators:  #'s - B        C - L       M - S       T - Z
 

Last Updated: November 22, 2021 03:00 PM

CMOS Inverter forms a Resonant LD Oscillator  -  This circuit uses a single CMOS inverter to form a series resonant LC oscillator.  The values shown set the oscillation at about 125KHz but the other frequencies are possible by changing the main LC values . . . Hobby Circuit designed by David A. Johnson P.E.-March, 2002

CMOS Inverter Parallel LC Oscillator -  I have used this parallel resonant LC oscillator circuit countless times.  The oscillator frequency is determined by the inductor and capacitor values.  I have shown an adjustable inductor to make it easy to set the frequency to a specific value. . . Circuit by David A. Johnson P.E.-March, 2002

CMOS Inverters Form 125Khz Oscillator -  This circuit inverts the LC components so the inductor is grounded.  Two inverters are needed to produce the needed oscillation.  Again, the values shown set the frequency at 125KHz but can be changed to produce other frequencies . . . Hobby Circuit designed by David Johnson P.E.-March, 2002

CMOS Nand Gate Forms Gated 125Khz Oscillator -  This circuit is uses a NAND gate as an inverter.  The gate allows the oscillator to be gated on and off.  Again, the values shown set the frequency at 125KHz but can be changed to produce other frequencies. . . Circuit by Dave Johnson P.E.-March, 2002

CMOS Oscillator, Draws Only 0.5ua -  if truly low power oscillators interest you, this circuit draws a mere 2 microwatts (500nA) from a 6v battery.  it uses a very inexpensive C-MOS IC to produce a frequency of 2Hz.  However, by changing the component values you can push it to 300Hz . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

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

Crystal Controlled 1KHz Signal Generator -  A while back I got an email from a Discover Circuits visitor.  He needed a way to calibrate a RPM display for a big diesel engine.  The engine had a tachometer output which produced 12 pulses per rotation with an amplitude of about 5v RMS.  The full scale reading on the engine’s RPM speed display dial was 5, 000. . . Circuit by David Johnson P.E.-May, 2012

Circuits Designed by Dave Johnson, P.E. :
Button Battery Cell Internal Resistance Measurement Circuit -  The open cell voltage of a small silver oxide button cell battery remains very close to 1.5 volts over most of the life of the cell.  However, there is a relationship between battery health and the internal resistance of the cell.   This circuit when used. . . Circuit by Dave Johnson P.E.-July, 2006

Cheap Low Power 3v 2hz Oscillator -  This is yet another method to generate low frequency output pulses.  The circuit uses an inexpensive under-voltage monitor IC and a couple of cheap MOSFETs.  it could easily be modified to produce pulse frequencies from about one cycle per minute to a maxim . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

CMOS Inverter 125khz LC Oscillator -  This circuit uses a single CMOS inverter to form a series resonant LC oscillator.  The values shown set the oscillation at about 125KHz but the other frequencies are possible by changing the main LC values. . . Circuit by David Johnson P.E.-March, 2002

Capacitance Proximity Switch
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Links to electronic circuits, electronic schematics and designs for engineers, hobbyists, students & inventors:

Canary Sound Effect -  An electronic version of a chirping canary.  May be used as an alarm, a sound effects generator or perhaps a replacement doorbell __ Designed by Andy Collison

CD4093 Pulse Width Modulator -  The IC used is a CMOS type MC14093, a quad 2-input NAND Schmitt trigger.  if you wish, it can be directly interchanged with the CMOS MC14011 but this type is noisy.  The speed is adjustable from 0-max.  Max rpm is 2/3 the supply voltage __ Designed by Tony van Roon  VA3AVR

Cheap Low Power 3v 2hz Oscillator -  This is yet another method to generate low frequency output pulses.  The circuit uses an inexpensive under-voltage monitor IC and a couple of cheap MOSFETs.  it could easily be modified to produce pulse frequencies from about one cycle per minute to a maxim . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Circuit Detects Current Pulse -  01/06/94 EDN Design Ideas:  The pulse detector provide as a visible indication of positive and negative current pulses.  The pulses amplitudes can vary from20 to150 mA.  The pulses durations can range from10 to40 msec, and their repetition rate can span40 to180 pulses/minute Design by Richard McGillivray, Grey Bruce Regional Health Centre, Owen Sound, Ontario, Canada

Circuit distorts duty cycle for CML inputs -  5-Aug-04 EDN Design Ideas:  To test a gigabit-speed data-recovery chip, you need a clock with a controllable duty cycle.  Because most pattern and clock generators have a fixed duty-cycle output of 50%, the design may require a small circuit to distort the duty cycle.  The signal with controllable duty cycle drives a standard CML (current-mode-logic] input with on-chip termination resistors Design by Dieter Verhulst and Xin Yin, Ghent University, Belgium

Circuit generates clean sine waves -  06/19/97 EDN Design Ideas:  Generating a square wave at a particular frequency is fairly simple.  Many techniques for doing so exist, using counters, flip-flops, and--everyone's favorite--the venerable 555 timer.  Generating a sine wave, however, is not nearly as simple or inexpensive.  Figure 1 shows a technique for generating a high-quality sine wave from a square-wave source Design by Med Dyer, Jabra Corp, San Diego, CA

Circuit produces variable frequency, duty-cycle -  24-Jul-03 EDN Design Ideas:  This design idea shows a simple, low-cost circuit that produces a highly accurate variable-frequency and variable-duty-cycle output (Figure 1).  Further, the duty cycle and frequency are independent of each other (excluding 0 and 100% duty cycle].  The method derives its accuracy and stability from the fact that the output is based on a crystal oscillator and divisions of the oscillator's frequency Design by Mark Reed, Texas Instruments, Dallas, TX

Circuit produces variable numbers of burst pulses -  24-Jun-04 EDN Design Ideas:  The add-on circuit in Figure 1 can produce one to 15 burst pulses with the same number of spaces between the bursts at a pulse width (frequency] that an external square-wave generator at the input sets.  The add-on circuit produces a variable number of bursts and a variable number of spaces between the bursts by using an external square-wave generator as a source Design by Michael Kornacker, Northrop Grumman Corp, Rolling Meadows, IL

Circuit samples Derivative of a waveform -  09/14/00 EDN Design Ideas:  Basic derivative (differentiating) circuits use a lowpass filter or an active operational-amplifier implementation.  These circuits need a large-value capacitor when differentiating a slowly varying signal.  Moreover, the circuits  Design by Joaquin Garcia

Clock Tunable, Filter Based Sine Wave Generator -  A feedback loop enclosed resonator can be made to oscillate.  This circuit’s sine wave generator takes advantage of this and eliminates the need for an amplitude control loop.  This circuit, a mildly modified form of the Regan resonant bandpass loop, is clock tunable and produces sine and cosine outputs.  __ Linear Technology/Analog Devices App Note, Mar 26th 2010

CMOS hex inverter generates low-distortion sine waves -  06/09/05  EDN Design Ideas:  Audio signal source uses hex inverter and handful of passives Design by Al Dutcher, West Deptford, NJ

CMOS IC 1 kHz Audio Oscillator -  This circuit consists of a CMOS square wave oscillator on a frequency of approximately 1 kHz.  The RC filter, which has a roll-off frequency of 500 Hz, filters the harmonics, providing a sine-wave output.  The oscillator has many uses; sidetone circuits in transmitters and signal injectors for audio tests are just two __ Designed by Peter Parker VK3YE

CMOS Inverter 125khz LC Oscillator -  This circuit uses a single CMOS inverter to form a series resonant LC oscillator.  The values shown set the oscillation at about 125KHz but the other frequencies are possible by changing the main LC values. . . Circuit by David Johnson P.E.-March, 2002

CMOS Inverter forms a Resonant LD Oscillator  -  This circuit uses a single CMOS inverter to form a series resonant LC oscillator.  The values shown set the oscillation at about 125KHz but the other frequencies are possible by changing the main LC values . . . Hobby Circuit designed by David A. Johnson P.E.-March, 2002

CMOS Inverter Parallel LC Oscillator -  I have used this parallel resonant LC oscillator circuit countless times.  The oscillator frequency is determined by the inductor and capacitor values.  I have shown an adjustable inductor to make it easy to set the frequency to a specific value. . . Circuit by David A. Johnson P.E.-March, 2002

CMOS inverter VCO tunes octave to UHF -  11/19/98 EDN Design Ideas:  NOTE:  File contain several designs.  Scroll to find this one.  A robust and versatile vco provide as a stable output to 300 MHz (Figure 1).  The circuit's simplicity, unconditional stability, and consistent high-drive capability over an octave make the oscillator ideal for many applications, such as synthesized sources, local oscillators, and transmitters.  The AHC logic family (Texas instruments, www. Ti.com) makes the circuit's performance possible.  AHC is a relatively new line of CMOS logic whose high speeds and good noise performance allow oscillator operation into regions in which bipolar-junction-transistor and FET designs prevail. Design by Shawn Stafford, AM Communications Inc, Quakertown, PA  

CMOS Inverters Form 125Khz Oscillator -  This circuit inverts the LC components so the inductor is grounded.  Two inverters are needed to produce the needed oscillation.  Again, the values shown set the frequency at 125KHz but can be changed to produce other frequencies . . . Hobby Circuit designed by David Johnson P.E.-March, 2002

CMOS Nand Gate Forms Gated 125Khz Oscillator -  This circuit is uses a NAND gate as an inverter.  The gate allows the oscillator to be gated on and off.  Again, the values shown set the frequency at 125KHz but can be changed to produce other frequencies. . . Circuit by Dave Johnson P.E.-March, 2002

CMOS Oscillator, Draws Only 0.5ua -  if truly low power oscillators interest you, this circuit draws a mere 2 microwatts (500nA) from a 6v battery.  it uses a very inexpensive C-MOS IC to produce a frequency of 2Hz.  However, by changing the component values you can push it to 300Hz . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

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

CMOS Toggle Flip Flop using Push Button -  The circuit below uses a CMOS dual D flip flop (CD4013) to toggle a relay or other load with a momentary push button.  Several push buttons can be wired in parallel to control the relay from multiple locations.  A high level from the push button is coupled to the set line through a small (0.1uF) capacitor.  The high level from the Q output __ Designed by Bill Bowden

Compensation Extends Oscillator's Range -  12/05/96 EDN Design Ideas:  A simple technique provide as phase compensation for the oscillator in Figure 1a.  in this circuit, a tungsten lamp regulates the amplitude of a crystal bridge oscillator.  This type of oscillator produces a very low-distortion output at a very stable frequency.  The op amp must have a negligible phase shift at the operating frequency, which Design by Israel Schleicher, Green Spin, Bakersfield, CA

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  Design by Glenn Chenier, Allen, TX

Convert any signal to exactly 50% duty cycle -  06/25/13  EDN Design Ideas:  How would you process a variable frequency signal to always maintain a 50% duty-cycle? Here's one way Design by Jim McLucas

Convert periodic waveforms to square waves -  08/16/01 EDN Design Ideas:  Converting periodic waveforms to square waves is an integral part of extracting a clock signal from data, creating waveform generators, and making timing-pulse generators.  Any square-wave-conversion circuit isvaluable when the square wave's duty cycle is variable and controllable.  Figure 1 shows a circuit that has these attributes and can drive several TTL-compatible loads Design by Ron Mancini, Texas Instruments, Bushnell, FL

Converters Yield Droop-Free S/H -  11/17/11  EDN Design Ideas:  (Originally published in the January 23, 1986, EDN-Design ideas) in low-frequency applications, many monolithic sample/hold circuits suffer a droop rate that can cause an unacceptably large output error.  The S/H circuit in Fig 1 eliminates droop error by operating two 8-bit multifunction converters back to back.  The circuit requires a 5V supply and accepts analog inputs between 0 and 2.5V (although you can scale and offset any input signal to fall within this range)  Design by TG Barnett, The London Hospital Medical College, London, UK

Countdown timer may never need battery replacement -  06/23/05  EDN Design Ideas:  Processor-based timer draws microamps Design by Mark E Buccini, Texas Instruments, Houston, TX

CPLD connects two instruments with half-duty-cycle generator -  10/11/07 EDN Design Ideas:  A clocking circuit programmed into a CPLD generates a synchronizing pulse for a slower instrument at half the duty cycle of a faster instrument Design by Yu-Chieh Chen and Tai-Shan Liao, National Applied Research Laboratories, Hsinchu, Taiwan

Crystal Controlled 1KHz Signal Generator -  A while back I got an email from a Discover Circuits visitor.  He needed a way to calibrate a RPM display for a big diesel engine.  The engine had a tachometer output which produced 12 pulses per rotation with an amplitude of about 5v RMS.  The full scale reading on the engine’s RPM speed display dial was 5, 000. . . Circuit by David Johnson P.E.-May, 2012

Crystal Oscillator overcomes typical Drawbacks -  08/17/98 EDN Design Ideas:  NOTE:     FILE
has several circuits, scroll to this one.  Most crystal oscillators suffer from three drawbacks: They can't drive much of a load, the duty cycle isn't adjustable, and the duty cycle drifts.  The crystal oscillator in Figure 1 solves these problems.  Three parallel gates drive heavy loads, the duty cycle is adjustable from 25 to 75%; and feedback minimizes the drift. Design by Ron Mancini and Jeff Lies, Harris Semiconductor, Melbourne, FL

Crystal-Oscillator Is Ultralow Power -  EDN-Design ideas -- 09/24/12    Build a crystal-oscillator circuit that draws only about 5 μA of current. Design by Thomas Mathews, Texas Instruments

Current-Feedback Amp Yields Simple Circuit Oscillator -  06/08/95 EDN Design Ideas:  Using a current-feedback op amp, you can generate high-frequency sine waves with larger amplitude than conventional op-amp-based designs.  The circuit in Fig 1 uses four passive components, connecting one capacitor to the compensation node (another op amp that has this pin a Design by Celma and P A Martinez, University of Zaragoza, Spain

Current-Feedback Amps Square Up Fast Signal -  06/23/94 EDN Design Ideas:  Using current-feedback amplifiers to convert signals from sine waves to square waves for DSP confers advantages over the more common comparator approaches.  Current-feedback amplifiers have wide bandwidths and relatively small and constant propagation delays.  These small, constant delays help meet the setup-and-hold requirements of Design  Rea Schmidt, Comlinear Corp, Fort Collins, CO

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Signal Generators:  #'s - B        C - L       M - S       T - Z


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