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Signal Generator Circuits

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

Last Updated: November 22, 2021 02:42 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 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 Karl’s 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 David A. 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

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:

Variable Frequency PWM -  Schematic only, no circuits description.   __ Designed by Tony van Roon  VA3AVR

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.    Design by Barry Harvey, Elantec Corp, Milpitas, CA

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 noice 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 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 Johnson P.E.-March, 2002

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 im Design by Henry Walmsley, Farnborough, UK

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 Karl’s 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 David A. 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 -  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

Video Generators -  many test picture generation circuits __ Designed by Mijo Kovacevic, S51KQ

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 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.  IC 1 is a V/F converter Design by Yongping Xia, EBT Inc, Torrance, CA

Waveform Generator Minimizes Amplitude Dependency -  EDN Design Ideas:  May 26, 2011    improve a waveform generator's immunity to changes in power-supply voltage.   Design by Marián Štofka, Slovak University of Technology, Bratislava, Slovakia

Waveform Generator provides Flexible Frequency tuning for Sensor Measurement -  12/17/04  EDN Design Ideas:  Variable-resistance sensors convert a fixed dc excitation voltage or current into a current or voltage that's a straightforward function of the quantity undergoing measurement.  in another class of sensors, moving objects or fluids p Design by Colm Slattery Analog Devices, Limerick, Ireland

Weighting Filter for Audio Measurements -  For noise measurements.  ideal for use with the AC Millivoltmeter above   __ Designed by Rod Elliott  ESP

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

Wide-range voltage regulator automatically selects operating-mode -  06/09/05  EDN Design Ideas:  Regulator seamlessly adapts to wide output range Design by Joel Setton, Crolles, France

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 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 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 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

WIFI CAN Antenna -  Got no dough for a commercial WiFI antenna? Looking for an inexpensive way to increase the range of your wireless network? A tin can waveguide antenna, or Cantenna, may be just the ticket.  This design can be built for under $5 U.  S.  and reuses a food, juice, or other tin can __ 

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

Yield Frequency Locked Triangle Waves -  02/02/98 EDN Design Ideas:  The circuit in Figures 1 and 2 generates frequency-locked triangle waves of constant amplitude.  it uses readily available TTL and other older-technology parts.  The circuit portion in Figure 1 comprises the frequency dividers, counters, and converter.  The portion in Figure 2 contains current sources, output circuits,  Design by Daniel Dufresne, Decatron, St Bruno, PQ, Canada

Zener test serves as DC source -  11/25/04  EDN Design Ideas:  This design idea     describes a versatile test circuit for zener diodes after yet another misread zener diode had infiltrated the ranks of 1N4148 diodes assembled on a pc board.  As a bonus, the circuit can serve as a moderate-voltage,  Design by John Jardine, JJ Designs, West Yorkshire, UK

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


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