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Oscillators:  Square Wave
#'s - C        D - R        S - Z
Oscillator Circuits -- Main Page

Last Updated on: Wednesday, July 16, 2014 06:35 AM


Circuits Designed by Dave Johnson, P.E. :

  • 200MHz400MHz VOLTAGE CONTROLLED OSCILLATOR
    If you need a clean emitter coupled logic (ECL) type signal between 200MHz and 400MHz this circuit works fine. It uses four voltage-controlled capacitors to change the frequency.
  • CMOS INVERTER 125KHz LC OSCILLATOR
    This circuit uses a single CMOS inverter to form a series resonant LD oscillator.   The values shown set the oscillation at about 125KHz but other frequencies are possible by changing the main LC values.
  • 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.  Once set the frequency is fairly stable over supply voltage variations and temperature changes.  The values shown are for 125KHz but the frequency can range from tens of kilohertz to tens of megahertz.   With a 74HCU04 type inverter, it will oscillate down to about 1.5 volts.  If the frequency is low, you can also use a 74C04 (CD4069) inverter.
  • 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.


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:
µC squares input signal -  12/19/96 EDN-Design Ideas....Converting a random-width pulse to a signal with the same frequency but with a 50% duty cycle isn't easy, especially when the specified frequency range is large…. [Design Idea by Yongping Xia, Philips Lighting Electronics Co, Torrance, CA]
200MHz-400MHz Voltage Controlled Oscillator (VCO) -  If you need a clean emitter coupled logic (ECL) type signal between 200MHz and 400MHz this circuit works fine. It uses four voltage-controlled capacitors to change the frequency.... [Designed by David A. Johnson]
AF Generator -  My generator can produce sine- and squarewaves with frequencies between 1 Hz and 100 kHz and amplitudes ranging from zero to 1.55 Veff in 600 Ohms. Sinewave distortion is 0.1% or less between 20 Hz and 20 kHz, somewhat greater outside this region. The output voltage …(electroninc design added 04/05/06)
An OscillatorSawtooth & Square Wave Output -  SimpleSingle Supply and Works Very well with Minimum Parts Count....(Circuit design added 12/08)
CMOS Iinverter 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.  Once set the frequency is fairly stable over supply voltage variations and temperature changes.  The values shown are for 125KHz but the frequency can range from tens of kilohertz to tens of megahertz.   With a 74HCU04 type inverter, it will oscillate down to about 1.5 volts.  If the frequency is low, you can also use a 74C04 (CD4069) inverter. …. [Designed by David A. Johnson]
CMOS Inverter 125kHz LC Oscillator -  This circuit uses a single CMOS inverter to form a series resonant LD oscillator.   The values shown set the oscillation at about 125KHz buth other frequencies are possible by changing the main LC values.... [Designed by David A. Johnson]
CMOS Inverters Form 125kHz Oscillator -  This circuit is similar to schematic CMOS INVERTER 125KHz LC OSCILLATOR but 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.... [Designed by David A. Johnson]
CMOS Nand Gate Forms Gated 125kHz Oscillator -  This circuit is similar to schematic number 116 but 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.... [Designed by David A. Johnson]
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.... [Designed by David A. Johnson]
Convert periodic waveforms to square-waves -  16-Aug-01 Issue of EDN  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 Idea by Ron Mancini, Texas Instruments, Bushnell, FL]
 

Oscillators:  Square Wave  -  #'s - C        D - R        S - Z
Oscillator Circuits -- Main Page

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