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Oscillators:  #'s - D      E - R      S - Z

Power Supplies -- Main Page       Oscillator Circuits -- Main Page
 

Last Updated: October 24, 2017 02:55 PM

Circuits Designed by Dave Johnson, P.E. :

VCO from CMOS Schmitt Trigger IC - 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

Version 4 of a Ultra Low Current Oscillator - The circuit below was inspired by a programmable unjunction transistor (PUJT) circuit sent to me by Karl Isbrecht.  In Karls circuit, the unijunction circuit made click sounds in a speaker and consumed very little power.  His circuit reminded me that a PU . . . Hobby Circuit designed by Dave Johnson P.E.-January, 2010

Very Low Power Astable Multivibrator - This classic circuit draws only 200 nanoamps from a 1.5v supply. . . Circuit by Dave Johnson P.E.-June, 2000

Very Low Power Gated Crystal Oscillator - The circuit gates the output of a continuously operating 32KHz crystal oscillator to the input of a C-MOS buffer when clock pulses are needed.  The technique gets around the problem of a slow starting crystal oscillator by keeping the oscillator going and switching on a transistor power stage only as needed. . . Circuit by David A. Johnson P.E.-June, 2000

Very Low Voltage Oscillator Circuit - OK, you may not ever need an oscillator to function using a power supply voltage below one volt, but if you ever do need one, here is one way to do it.  Getting any electronic circuit to operate below one volt is a real challenge.  Typical silicon bipolar . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2008


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

V/F Converter Draws Flea Power -  04/24/97 EDN-Design Ideas - The V/F converter in Figure 1 is unique because it draws less than 30 A from one unregulated supply while converting bipolar input voltages.  It produces three CMOS -compatible, 0to 10-kHz outputs one (F+]that becomes active when the input voltage is positive, another (F]that takes __ Circuit Design by W Stephen Woodward, University of North Carolina, Chapel Hill, NC

Variable Frequency Oscillator -  The first stage built was the VFO shown above in Figure 1.  The oscillator portion is based upon Figure 4.15 from EMRFD.  The VFO resonator tank is isolated from the JFET by tapping down as shown.  This is an outstanding VFO topology.  __ 

Variable Gain Control Produces Pure Sine Wave -  10/27/94 EDN-Design Ideas - The circuit in Fig 1 delivers a pure, buffered, and level-controlled sine wave.  With no tuning requirements, the circuit works with all crystals up to about 30 MHz.    __ Circuit Design by Barry Harvey, Elantec Corp, Milpitas, CA

VHF Overtone Crystal Oscillators -  VHF overtone crystals can be difficult to use due to the many frequencies at which the crystal is perfectly happy to oscillate.  A typical 100 MHz, 5th-overtone crystal will oscillate at approximately 20 MHz, 60 MHz, 100 MHz, and even 140 MHz, not to mention other, unintended modes that such crystals often have.  Most VHF overtone oscillators use some sort of tuned circuit or frequency selective filter to select the desired mode and reject the other, equally active modes.  The oscillator circuit shown below uses a simple tuned circuit to select the desired mode and is suitable for VHF crystals, including high overtone types __  Contact:  Charles Wenzel of Wenzel Associates, Inc.
VCO covers 300MHz to 500MHz based on Maxim MAX2608 VCO -  The datasheet says this VCO covers 300 to 500 Mhz,  in this test setup with one coil it covers 350 to 475 Mhz with the controlling voltage.  The output should be about -10dBm, but it's -20dBm.  The stability and sideband noise was not good enough for my HAM radio project, sorry.   But I'm sure it will be perfect to be used with a PLL. __ Designed by Thomas Scherrer OZ2CPU

VCO footprints & layout considerations to improve performance -  Application Note__ MiniCircuits.com

VCO from CMOS Schmitt Trigger IC -  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

VCO fundamentals & concepts -  Application Note__ MiniCircuits.com

VCO Has Digitally Programmable Center Frequency -  04/25/96 EDN-Design Ideas - The circuits in Figure 1 illustrates a narrowband VCO, which has a digitally programmable center-frequency ratio of greater than 2-to-1.  With a VCO having center-frequency ratio (F HIGH/FLOW]of greater than 2-to-1, you can derive any output frequency by simple binary division __ Circuit Design by Paul Sofianos, Motorola LICD, Chandler, AZ

VCO produces positive & negative output frequencies -  12/25/03  EDN-Design Ideas - The circuit in Figure 1 is a quadrature-output VCO that provide as both positive and negative output frequencies, depending on the polarity of the control-voltage input.  The circuit provide as a function that designers traditionally __ Circuit Design by Henry Walmsley, Farnborough, UK

VCO test methods -  Application Note__ MiniCircuits.com

VCO uses programmable logic -  14-Nov-02 EDN-Design Ideas - A VCO (voltage-controlled oscillator] is an analog circuit, so you cannot find it in the libraries for the design of digital programmable chips.  When you need such a circuit for synchronization or clock multiplication, you need to find a circuit that works with the standard digital functions, such as AND and NAND __ Circuit Design by Susanne Nell, Breitenfurt, Austria

VCO using the TL431 reference -  10/10/13  EDN-Design Ideas - The ubiquitous TL431 voltage reference has found something else its good at __ Circuit Design by R O Ocaya

VCOM adjustment uses any logic-supply voltage -  09/30/04 EDN-Design Ideas - All TFT [thin-film-transistor] LCD panels require at least one appropriately tuned VCOM signal to provide a reference point for the panels backplane.  The exact value of VCOM  varies Page includes several designs.  Scroll to find this one __ Circuit Design by Peter Khairolomour and Alan Li, Analog Devices, San Jose, CA

Version 4 of a Ultra Low Current Oscillator -  The circuit below was inspired by a programmable unjunction transistor (PUJT) circuit sent to me by Karl Isbrecht.  In Karls circuit, the unijunction circuit made click sounds in a speaker and consumed very little power.  His circuit reminded me that a PU . . . Hobby Circuit designed by Dave Johnson P.E.-January, 2010

Very Low Power Astable Multivibrator -  This classic circuit draws only 200 nanoamps from a 1.5v supply. . . Circuit by Dave Johnson P.E.-June, 2000

Very Low Power Gated Crystal Oscillator -  The circuit gates the output of a continuously operating 32KHz crystal oscillator to the input of a C-MOS buffer when clock pulses are needed.  The technique gets around the problem of a slow starting crystal oscillator by keeping the oscillator going and switching on a transistor power stage only as needed. . . Circuit by David A. Johnson P.E.-June, 2000

Very Low Voltage Oscillator Circuit -  OK, you may not ever need an oscillator to function using a power supply voltage below one volt, but if you ever do need one, here is one way to do it.  Getting any electronic circuit to operate below one volt is a real challenge.  Typical silicon bipolar . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2008

VFO Buffer -  In the first design of the receiver, this buffer was used with an FET VFO oscillator followed by a filter and a 2N5109 amplifier.   __ Designed by Web David White, WN5Y

VFO from 2001 ARRL Handbook 4.20 -  Schematic only __ Designed by Jim Osburn, WD9EYB

VFO/Buffer -  It's basically a standard Hartley oscillator, followed by Roy Lewallen's buffer (page 14.20 of the 2001 Handbook).  Output is +7 dBm into 50 Ohms.  Don't be tempted to add a gate diode, this circuit doesn't need it, and it will degrade the phase noise performance, according to Ulrich Rohde.  It should be suitable __ Designed by Leon Heller

VHF Overtone Crystal Oscillators -  VHF overtone crystals can be difficult to use due to the many frequencies at which the crystal is perfectly happy to oscillate.  A typical 100 MHz, 5th-overtone crystal will oscillate at approximately 20 MHz, 60 MHz, 100 MHz, and even 140 MHz, not to mention other, unintended modes that such crystals often have.  Most VHF overtone oscillators use some sort of tuned circuit or frequency selective filter to select the desired mode and reject the other, equally active modes.  The oscillator circuit shown below uses a simple tuned circuit to select the desired mode and is suitable for VHF crystals, including high overtone types __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Volt/F Converter Draws Flea Power -  04/24/97 EDN-Design Ideas - The V/F converter in Figure 1 is unique because it draws less than 30 A from one unregulated supply while converting bipolar input voltages.  It produces three CMOS -compatible, 0to 10-kHz outputs one (F+]that becomes active when the input voltage is positive, another (F]that takes __ Circuit Design by W Stephen Woodward, University of North Carolina, Chapel Hill, NC

Voltage Controlled Amplifier -  In truth this, like many (most) VCAs is really a current controlled amplifier but there is really not too much difference since if you want to turn a CCA into a VCA you simply feed the current input from a voltage via a voltage to current converter (a.  k.  a.  'resistor')  __ Designed by Richard Torrens

Voltage Controlled Current Source with Ground Referred Input & Output -  A flying capacitor device such as the LTC1043 can produce a precision voltage differential over a wide common mode range.  Here it converts a ground referred input voltage directly to a differential voltage across a fixed resistor which then forces a precise current sourced at the circuit output.  __ Linear Technology/Analog Devices App Note, Jun 21, 2011

Voltage Controlled Low Frequency Oscillator with Sync  -  Voltage Controlled Low Frequency Oscillator with Sync__ 

Voltage Controlled Oscillator VCO -  The oscillation frequency of the voltage controlled oscillator is controlled by the output of the PLL synthesizer and does the stable oscillation of 119.3 MHz __ Designed by Seiichi Inoue

Voltage Controlled Resistor -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

Voltage Controls Sine-Wave Frequency -  08/17/95 EDN-Design Ideas - The circuit in Fig 1 generates a 50-Hz to 1-kHz sinusoidal waveform that exhibits lower than 60-dB THD.  The input voltage controls the output frequency with the relationship 1 kHz/V.  The output amplitude is invariant with frequency over the entire operating range.  IC1 is a V/F converter __ Circuit Design by Yongping Xia, EBT Inc, Torrance, CA

VTSE - Type 1 (Voltage Controlled) Solar Engine -  The "Variable Threshold Solar Engine" is Wilf Rigter's 1381-based design -- with a variable "trip" threshold. __ Designed by Wilf Rigter

Vx2SE - Type 1 (Voltage Controlled) Solar Engine -  The VTSE uses the popular 1381 chip and that is its main advantage.  The potentiometer (or two fixed resistors) connects one leg between the output and input of the 1381 and the other leg to the supply voltage.  These resistors acts like a voltage divider when the SE is off and the 1381 output is low.  In that case, the voltage that appears at the 1381 input is determined by the ratio of the pot or the two resistors and is usually set for 2 times rated 1381 voltage.   __ Designed by Wilf Rigter

What I had to do to stabilize a VFO -  From the basic homebrew literature (QRP Classics, DeMaw's notebooks, various ARRL Handbook projects, etc) , I could never get VFO stability that really satisfied me. __ Designed by John Seboldt, K0JD

Wide Frequency Range 555 VCO -  The 555 frequency can be varied via adjusting the voltage at pin 5.  However, the range and linearity of frequency adjustment is very limited.  This is a way to greatly improve performance using the inverted 555 timer circuit that was previously posted.555 VCO Schematic Current source Q2 is connected in the common base __ Designed by Jim Keith

Wide Modulation Bandwidth Measurements -  AN-95-004 Application Note__ MiniCircuits.com

Wide Swing Variable Crystal Oscillator -  amateur radio construction projects.   __ Designed by Peter Parker

Wide-swing Variable Crystal Oscillator -  Timing and oscillator circuit diagrams / circuit schematics __ Designed by Peter Parker VK3YE

Wien Bridge Oscillator -  The OpAmp Wien-bridge oscillator provides a nice view into classic oscillator design using feedback analysis.  Feedback analysis reveals if your circuit is stable (well behaved) or unstable (spice design)  __ Designed by Andrew R. Morris

Wien Bridge Oscillator keeps THD below One PPM -  11/10/94 EDN-Design Ideas - The Wien-bridge sine-wave oscillator uses a light bulb to stabilize its amplitude.  The circuit doesn't have a light bulb; it sports several enhancements that lower its distortion __ Circuit Design by Jeff Smith, Analog Devices, Wilmington, MA

Wien Bridge Oscillator Rail-to-Rail Sine Wave Generator  -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

Wien Bridge Oscillator with SPICE simulation -  Timing and oscillator circuit diagrams / circuit schematics__ 

Wien Bridge Oscillator-42003.0 -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

Wien-Bridge oscillator has simplified frequency control -  In this article, a modified version of the classical circuit that uses a single low-cost variable resistor for frequency control will be described.   __ Designed by Ramon Vargas 20-8-04

Wien-bridge oscillator is reborn -  06/13/02  EDN-Design Ideas - In 1940, William Hewlett and David Packard launched a product from a garage.  The product was a Wien-bridge oscillator.  It consisted of a single-pole highpass filter in series with a single-pole lowpass filter.  To keep the gain cons __ Circuit Design by Michael Fisch, Agere Systems, Longmont, CO

Wien-bridge Theremin -  This circuit is a basic Theremin with only a pitch control.  It uses the "heterodyne" technique, as did Theremin's original instrument.  Heterodyning is advantageous in its simplicity, and is made further attractive in this design by eliminating the coils that are usually hard to find (electronic design 10/05)  __ Designed by Arthur Harrison

Xtal parameters with spectrum analyzer & tracking generator -  Crystal Parameters --- Experiments with a Tracking Generator + Spectrum Analyzer __ Contact Vasily Ivanenko

XTAL switcher using diodes -  Ham Radio - Other __ Designed by Guy Roels ON6MU

Xtal Tester -  This is a simple Xtal tester circuit.  T1 and Xtal have formed an oscillator.  C1 and C2 are voltage divider for oscillator.  if the Xtal is safe, the oscillator will work well and its output voltage will be rectified by C3, C4, D1 and D2, then T2 will run and LED will light.  The circuit is suitable to test 100KHz - 30MHz Xtal. __ Contact IQ Technologies

XTAL-Controlled FM TX (V6) -  My FM Wireless microphone V5 has been very popular, both as a beginners project and as a kit.  It is interesting that it has also been the biggest cause of lots of e-mail, the most common question being How can I make it crystal controlled?.  The oscillator can be made crystal controlled; replace the 2p7 with a 5th harmonic crystal.  The oscillator will then be very stable, so stable in fact, that it cannot even be modulated! This means that you could only use it to send CW (Morse code)  __ Designed by Harry Lythall-SM0VPO

Yaesu FT-897, FT-857 & FT-817 transceiver-PC interface (YFPI) -  This interface is used to fully control a transceiver, from a personal computer, when operating digital amateur radio modes (made in January 2006)  __ Designed by Bjarke Korsgaard

Zener-based - Type 1 (Voltage Controlled) Solar Engine -  This design uses a Zener diode to determine the voltage trip level.  Simple variants of this design use LEDs or plain old diodes in series to accomplish the same thing. __ Designed by Wilf Rigter

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Oscillators:  #'s - D      E - R      S - Z

 


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