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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

Circuits Designed by Dave Johnson, P.E. :
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 . . . Hobby Circuit designed by Dave Johnson P.E.-March, 2002

Gated Crystal Oscillator with Very Low Power -  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 . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Generate Short Delayed Pulse -  This circuit generates a short 10ms pulse 15 minutes after a “start” pushbutton switch is activated . . . Hobby Circuit designed by David Johnson P.E.-October, 2005

Highly Stable Lower Power Oscillator -  This circuit works much like the classic 555 timer, but draws only about 1.5 microamps from a 3 volt battery.  it is highly stable under varying temperature and supply voltages. . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2000

Honeybee Counter -  I designed a circuit similar to this one a long time ago to help a beekeeper count the number of bees going into or out of a hive.  The low power circuit uses a slotted opto-sensor to detect the passing bees.  The circuit advances an electronic counting. . . Circuit by David A. Johnson P.E.-July, 2000

Indicates when it is Time to Dust -  I have used the circuit below for many different applications, which require ultra low power drain.  it uses a single CA4013 flip/flop.  One section forms a pulse generator.  The generator produces 100uS pulses at a rate of about 1 per secondCircuit Solution by David Johnson P.E.-May, 2006

Indicates when it is Time to Dust -  I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough.  I have not yet built and tested this circuit completely but in concept it should work. . . Circuit by David Johnson P.E.-June, 2000

It's Time to Dust Indicator -  I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough.  I have not yet built and tested this circuit completely but in concept it should work . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

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

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 . . . Hobby Circuit designed by Dave Johnson P.E.-March, 2002

Gated Crystal Oscillator with Very Low Power -  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 . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Gated Oscillator Emulates a Flip-Flop -  03/16/95 EDN Design Ideas:  The gated oscillator in Fig 1 holds its existing state when disabled rather than being forced high or low-a singular property.  Further, you can generate an output at one-half the input frequency if you choose R1 and C so that the oscillator changes state just once when its input goes high.  This configuration eliminates a flip-flop.    Design by Einar Abell, ADA Instruments, Three Rivers, CA

Gated RC Phaseshift Oscillator -  Scroll down.  The last circuit is a simpler R-C phase shift oscillator, but this is one with a difference: it is gated, i.  e.  it can be turned on by an input signal.  Earth the input and the oscillator stops, connect it to 5v and the oscillator starts.  The oscillator will always start in the same fashion, with a positive edge  __ Designed by Richard Torrens

Gates Provide Low Cost Sine Wave Generator -  08/15/97  EDN Design Ideas:  One of the troubleshooting tests required for telephone/data twisted-pair copper lines is the determination of the attenuation factor.  The test uses frequencies of 300 to 4000 Hz to plot the attenuation performance.  Because many central-distribution lines Design by Adolfo Mondragon, Philips Components, Juarez, Mexico

Generate CID/CIDCW Analog Signals -  12/07/00 EDN Design Ideas:  A high-speed mP and active lowpass filters can generate CiD (caller-iD]and CiDCW (caller-iD-on-callwaiting] analog signals (Figure 1).  CiD data transmits at 1200 baud FSK between the first and second 20-Hz ring of an incoming call.  CiDCW uses a CAS (CPE Alert Signal]dual tone, PDF contains multiple circuits, scroll to find this circuit.    Design by Hans Krobath, EEC, Nesconset, NY

Generate frequencies with arbitrary relationships -  03/16/00 EDN Design Ideas:  The circuit in Figure 1 and the program in Listing 1 use an Atmel 89C2051 µC to generate a variety of frequencies that have no specific relationship to each other.  The example given here generates the following eight frequencies  Design by Sanjay Gupta

Generate Short Delayed Pulse -  This circuit generates a short 10ms pulse 15 minutes after a “start” pushbutton switch is activated . . . Hobby Circuit designed by David Johnson P.E.-October, 2005

Generate stabilized PWM signals -  08/17/00 EDN Design Ideas:   A standard technique for generating analog voltages using  µCs is to use a PWM output and filter the signal with a simple RC filter (Figure 1).  The voltage of the PWM signal is directly proportional to the µC's supply voltage, so Design by Martin Ossmann, FH, Aachen, Germany

Generate Swept Sine/Cosine Waveforms with Two Filters -  06/23/11 EDN Design Ideas:  Phase difference holds between 89° and 90°.  Demodulators, directional circuits, and other electronics applications often need two sine waves with a 90° difference in phase—a sine wave and its cosine wave.  Engineers typically use analog filters to create the phase shift.  This approach, however, offers a limited frequency range.  Using the circuit in Figure 1, you can make a swept sine/cosine pair at frequencies of less than 1 Hz to 25 kHz.   Design by John R Ambrose, Mixed Signal Integration, San Jose, CA

Generating-5 Volts from a 9 Volt Battery -  This is a basic 555 squarewave oscillator used to produce a 1 Khz tone from an 8 ohm speaker.  in the circuit on the left, the speaker is isolated from the oscillator by the NPN medium power transistor which also provides more current than can be obtained directly from the 555 (limit = 200 mA).  A small capacitor is used at the transistor __ Designed by Bill Bowden

Generator features programmable duty cycle -  10/26/00 EDN Design Ideas:  The simple pulse generator in Fig 1 allows you to program its output's duty cycle.  You apply your duty-cycle code to the B port of IC 1, a 7485 magnitude comparator.  The clock increments the 74193 4-bit counter, IC 2.  When the output of the counter is equal to or greater than your duty-cycle code, IC 3 resets the output flip-flop, IC 4, until the counter, IC 2, overflows.  Thus, your input code determines the output's duty cycle.    Design by Shwang-Shi Bai, Chung Shan Institute of Technology, Lung-Tan, Taiwan

Generator has independent pulse width, frequency -  11/11/99 - EDN Design Ideas:  A common circuit in electronics is the square-wave, astable multivibrator (one-shot) , which is useful for various purposes, such as timing circuits and audible alarms.  The most common way to generate the desired square wave is to use the inexpensive 555 timer.  The need sometimes arises for a square wave with fixed frequency but variable pulse width or vice versa.    Design by Davinder Oberoi

Generator provides 537 NTSC pattern -  12/03/98 EDN Design Ideas:  if you're involved in the television, CRT, or deflection-yoke business, the circuit in Figure 1  can prove useful for adjusting convergence and purity performance.  The circuit generates dots, 537-line- crosshatch, and negative-field (crosshatch- inverted) patterns.  You normally.      FILE
has several circuits, scroll to this one Design by Adolfo Mondragon, Philips Components, Juarez, Mexico

Gnat-power sawtooth oscillator works on Low supply voltages -  05/15/13  EDN Design Ideas:  Making basic analog circuit functions that operate from a low-voltage battery supply can be tricky.  Lack of headroom and the need to minimize supply and leakage currents are usually the biggest challenges.   Design by Bruce D Moore, Consulting Analog Enginee

HAM Radio BFO -  circuit diagram of beat frequency oscillator using BF494 and how to listen amateur radio communication on ordinary BC receiver.  __ 

Harmonic Oscillator -  Here is an easy-build high-performance VHF (or UHF?) local oscillator.  There are no PCB foil drawings to play with and no coils to wind.  There are two 90mm long copper wire inductors needed, but the good news is, you don't have to wind them.  The first unit makes an excellent 10mW (+10dBm) exciter to drive a VHF power amplifier __ Designed by Harry Lythall-SM0VPO

Hartley oscillator requires no coupled inductors -  10/26/06 EDN Design Ideas:  Examine a traditional Hartley oscillator circuit, and you'll note its trademark  a tapped inductor that determines the frequency of oscillation and provide as oscillation-sustaining feedback.  Although you can easily calculate the total inductance required for a given frequency Design by Jim McLucas

High-Fidelity Triangle-Wave Generator Consumes Only 6 µA -  16-Oct-03 EDN Design Ideas:  ideal triangle waves involve infinite d2V/dt2, so high-fidelity triangle waves entail very high bandwidths.  Micropower circuits have fairly low bandwidth, so generating good triangle waves with such circuitry becomes problematic.  The circuits of Figure 1 show two methods of generating triangle waves Design by Glen Brisebois, Linear Technology Corp, Milpitas, CA

Highly Stable Lower Power Oscillator -  This circuit works much like the classic 555 timer, but draws only about 1.5 microamps from a 3 volt battery.  it is highly stable under varying temperature and supply voltages. . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2000

High-Speed Pulse Generator Has Programmable Levels -  12/31/69 EDN Design Ideas:  Lilliputian dimensions associated with the submicron geometries of most digital and many analog processes result in much faster circuit operation.  As ICs  speed up, the rise and fall times of most pulse and function generators, which are typically 5 nsec, become inadequate for measuring time intervals lower than 20 nsec.  You can overcome this limitation with analog comparators or advanced CMOS logic gates, which create faster digital edges.   Design by John Guy, Maxim Integrated Products, Sunnyvale, CA

High-Speed Pulse Modulator Retains Signal Envelope -  06-Aug-09 EDN Design Ideas:  Modulated signals have the ac components they need to pass through transformers.  - The circuit in Figure 1 enables you to convert an arbitrary, relatively slowly varying voltage waveform to a new waveform in which the instantaneous values of the original waveform alternate with positive and negative signs.  The new waveform retains information about the original waveform, .    Design by Marián Stofka, Slovak University of Technology, Bratislava, Slovakia

High-Voltage DC Generator -  Voltage, by definition, is the electrical pressure that causes current to flow through a conductor.  When that pressure is sufficiently high, a high voltage is produced.  But how do we define high-voltage? is 100, 1000, or 10, 000 volts considered high voltage? When compared to 10 volts, they all can be considered high voltage __ Designed by Tony van Roon  VA3AVR

Honeybee Counter -  I designed a circuit similar to this one a long time ago to help a beekeeper count the number of bees going into or out of a hive.  The low power circuit uses a slotted opto-sensor to detect the passing bees.  The circuit advances an electronic counting. . . Circuit by David A. Johnson P.E.-July, 2000

I.F. Amplifier -  The i.F.  transformer primary has 18 turns, the secondary winding has 4 turns.  The capacitors across the iFT primaries are 82pF.  The input/output transformer has 12 turns, tapped at 3 turns from ground.  This transformer is wound on a ferrite core.  The MOSFETs are 3SK45's.  The diodes in the product detector are 1N34's.  I use a six pole SSB filter from a scrap CB.  The centre frequency is 7.8MHz.  The -6db bandwidth is about 2.5KHz.   __ Designed by EI9GQ homebrew radio

IF Signal Generator -  Here is a versatile circuit of iF signal generator which may be of interest to radio hobbyists and professionals alike. Transistors T1 and T2 form an astable multivibrator oscillating in the audio frequency range of 1 to 2 kHz.  RF oscillator is built around transistor T3.  Here again a 455kHz ceramic filter/resonator is employed for obtaining stable iF.  __ 

Improved PL Tone Encoder -  A significant amount of interest has been generated since my last article on a PL tone board.  Because of this interest I decided to improve on the old PL tone design.  Figure 1 is an inexpensive PL tone generator with significantly improved performance.  it has a much more stable tone frequency as well as the elimination of the loading problem on the output.  The transistor used in the old circuit would cause the tone frequency to change at high levels.  This month's circuit eliminates all those problems __ Designed by Radio Amateur Society of Norwich

Indicates when it is Time to Dust -  I have used the circuit below for many different applications, which require ultra low power drain.  it uses a single CA4013 flip/flop.  One section forms a pulse generator.  The generator produces 100uS pulses at a rate of about 1 per secondCircuit Solution by David Johnson P.E.-May, 2006

Indicates when it is Time to Dust -  I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough.  I have not yet built and tested this circuit completely but in concept it should work. . . Circuit by David Johnson P.E.-June, 2000

Injection-Lock a Wien-Bridge Oscillator -  10/31/12  EDN Design Ideas:  A low-distortion Meacham-bulb-stabilized Wien-bridge oscillator is used to acquire the FFT of a pure sinusoid of about 5 kHz.  I recently had the opportunity to investigate a new micropower 6-MHz LTC6255 op amp driving a 12-bit, 250k sample/sec LTC2361 ADC.  I wanted to acquire the FFT of a pure sinusoid of about 5 kHz.  The problem is that getting the FFT of a pure sinusoid requires, well, a pure sinusoid.  Most programmable signal generators, however, have fairly poor noise and distortion performance, not to mention digital “hash” floors, compared with dedicated op amps and good ADCs.  You can’t measure 90-dB distortion and noise using sources that are “60 dB-ish.  ”  Design by Glen Brisebois, Applications Engineer, Signal Conditioning group at Linear Technology

It's Time to Dust Indicator -  I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough.  I have not yet built and tested this circuit completely but in concept it should work . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Kick start a crystal oscillator in Spice -  05/27/99 EDN Design Ideas:  Starting up oscillator circuits and getting them to maintain oscillation in a Spice simulation is difficult.  Some high-frequency crystal circuits require days for the oscillation to reach steady state.  This PDF has several circuits, please scroll to find this one.    Design by Adam Chen, Cypress Semiconductor, Woodinville, WA

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


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