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 solutions & design ideas.

Got Designs?
Please eMail
if you want me to link to and/or post your original design
NOTE:  We make every effort to link to original material posted by the designer. 
Please contact us if our link is not to your site!  Thanks.

Oscillators:  Voltage Controlled (VCO)
#'s - D      E - S       T - Z

Oscillator Circuits -- Main Page


Last Updated: November 22, 2021 02:42 PM

Circuits Designed by Dave Johnson, P.E. :
Light to Frequency Converter - This circuit uses a CMOS version of the classic 555 timer, to form a light intensity to frequency converter.  A small PIN photo diode is used as the light detector.  The pulses produced are short, so in some applications you may want to stretch them or . . . Hobby Circuit designed by Dave Johnson P.E.-May, 2008

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-778-8407

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

Eight-pin C forms one-chip programmable VCO -  09/24/98 EDN-Design Ideas - NOTE :  multiple circuits, scroll to this one.  The circuit in Figure 1 uses a Microchip 8-pin C (PIC12C671]as a voltage-controlled oscillator (VCO].  Because  PIC12C671 has an internal 4-MHz oscillator, four-channel 8-bit A/D converters, and built-in power-reset circuitry, you need no external components to configure  VCO.  The C reads two analog inputs through AN0 and AN1 Design by Yongping Xia, Teldata Inc, Los Angeles, CA

Enhanced, three-phase VCO features ground-referenced outputs -  01/19/06 EDN-Design Ideas - Three-phase VCOs (voltage-controlled oscillators) see service in many applications, including power inverters and in electronic-music synthesis as control and modulation sources. A previous Design Idea describes a basis for a simple, three-phase VCO (Reference 1). However, adding a few components enhances the circuit's performance. Design by Harry Bissell Jr, Welding Technology Corp, Farmington Hills, MI

FLED-based - Type 1 (Voltage Controlled) Solar Engine -  This design uses a flashing LED to determine the solar engine's voltage trip level. __ Designed by Wilf Rigter

GBSE - Type 1 (Voltage Controlled) Solar Engine -  The "Gate Boost Solar Engine" is a new (6/2002) Wilf Rigter 1381-based design.  This uses an internal voltage doubler to turn on a FET more efficiently. __ Designed by Wilf Rigter

Glossary of VCO terms AN-95-003 -  AN-95-003 Application Note__ MiniCircuits.com

High Frequency 555 Oscillator -  360kHz is the absolute maximum as the 555 starts to malfunction with irregular bursts of pulses above this frequency.  To improve the performance of the oscillator, a 270R and 1n can be added as shown in the second circuit:__ 555-Timer

How VCO Parameters Affect Each Other -  AN-95-005 Application Note__ MiniCircuits.com

Inverters form three-phase VCO -  08/04/01 EDN-Design Ideas - You sometimes need an inexpensive VCO that can produce evenly spaced three-phase outputs over a wide frequency range.  You could use tracking all-phase filters with only one oscillator, but this technique is difficult to implement and offers limited range.  Other methods, such as using a DSP, are feasible, but they're complex and expensive Design by Al Dutcher, AL Labs, West Deptford, NJ

Inverting latches make Simple Circuit VCO -  06/19/97 EDN-Design Ideas - The output frequency of the simple VCO in Figure 1, which is synthesized from inverting latch stages, is tunable to an integer multiple of the input frequency by selecting which output phases feed back to the input multiplexer.  The circuit Design by Ed Nielson, VLSI Technology, Sophia Antipolis, France

Light to Frequency Converter -  This circuit uses a CMOS version of the classic 555 timer, to form a light intensity to frequency converter.  A small PIN photo diode is used as the light detector.  The pulses produced are short, so in some applications you may want to stretch them or . . . Hobby Circuit designed by Dave Johnson P.E.-May, 2008

Light to Frequency Converter -  Fout = 1.4kHz per microampere of photo diode current, IPD.  The LTC6990 is a precision silicon oscillator with a programmable frequency range of 488Hz to 2MHz.  It can be used as a fixed-frequency or voltage-controlled oscillator (VCO).  The LTC6990 is part of the TimerBlox family of versatile silicon timing devices.  A single__ Linear Technology/Analog Devices App Note, Jun 16th 2010

Line Stretchers Ease VCO Load-Pull Testing -  AN-450-02 App Note__ MiniCircuits.com

Low-cost biases VCOs for cable & TV -  11/20/97 EDN-Design Ideas - PLLs are useful in a variety of applications, most notably cable and TV tuners.    Design by Ravindra Ambatipudi, National Semiconductor Corp, Santa Clara, CA

Multilayer Capacitor Doubles as Varactor -  20-Mar-03 EDN-Design Ideas - Correct voltage drop and phase shift in transmission lines - The main purpose for building the circuit in Figure 1 is to study the idiosyncrasies of X5R, Z5U, and Y5V multilayer ceramic capacitors.  The circuit is also an inexpensive VCO (voltage-controlled oscillator] with only five components.  Many types of ceramic capacitors for surface-mount placement are on the market Design by Susanne Nell, Breitenfurt, Austria

Optimizing VCO/PLL Evaluations & PLL Synthesizer Designs -  AN-95-006 Application Note__ MiniCircuits.com

Oscillator Has Voltage-Controlled Duty Cycle -  01/20/11 EDN-Design Ideas - Adjust duty cycle with a pair of resistors.   [Design Ideas by Luca Bruno, ITIS Hensemberger Monza, Lissone, Italy] Design by Luca Bruno, ITIS Hensemberger Monza, Lissone, Italy

Panner Waveform Generator -  analog synth CV source for the Voltage Controlled Panner __ Designed by G. Forrest Cook

Phase locked loop fundamentals -  Application Note__ MiniCircuits.com

Precision Voltage-Controlled Current Sink Tests Power Supplies -  03/20/08  EDN-Design Idea    A simple voltage-driven current sink allow you to test the dynamic behavior of power supplies Design by Luca Bruno, ITIS Hensemberger Monza, Lissone, Italy

Programmable Clock Oscillator -  PIC-Tock video clock using a PIC16C61.Voltage controller oscillator that was designed as a wide range oscillator to generate clock pulses for a stepper motor drive system, frequency could be varied over1,000,000:1 __ Designed by Richard Torrens

Quadrature (sine/cosine) voltage controlled oscillator -  Several schematics on this page, scroll to find this one.  The first circuit is a dual ramp generator where the positive and negative ramps are generated separately.  This circuit was used as a ramp generator for a transistor curve tracer: the positive going ramp was used for testing NPN transistors and the negative ramp for testing PNP transistors.   __ Designed by Richard Torrens

Reducing power supply noise in VCO's -  Application Note__ MiniCircuits.com

Simple Circuit VCO, 300 to 500 Mhz -  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

Simple Circuit 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 Design by Peter Khairolomour and Alan Li, Analog Devices, San Jose, CA

Simplest 555 Oscillator -  The simplest 555 oscillator takes output pin 3 to capacitor C1 viaresistor R1.  When the circuit is turned on, C1 is uncharged and output pin 3 is HIGH.  C1 charges via R1 and when Pin 6 detects 2/3 rail voltage, output pin 3 goes LOW.  R1 now discharges capacitor__ 555-Timer

Spice Model Emulates VCO -  07/06/95 EDN-Design Ideas - A behavioral model treats a circuit as a black box, which you can describe using an equation or table.  Listing 1 is a Microsemi PSpice behavioral model that simulates the operation of a voltage-controlled oscillator (VCO].  The output signal of a VCO is VO= (2fOt], where A is the amplitude, t is the time variable Design by Dr. Bashir Al-Hashimi, Staffordshire University, Stafford, UK

Voltage Controlled Oscillators:   #'s - D      E - S       T - Z

HOME Schematics Index Hobby Corner Dave's Circuits Contact Info
Imagineering Ezine Dave Johnson, P.E. Faraday Touch Switches

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

Copyright  January, 1998 - November, 2021     David A. Johnson  All Rights reserved. 

 COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED!