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Oscillators:  Crystal
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Oscillator Circuits -- Main Page
 

Last Updated: December 31, 2017 06:44 AM

Circuits Designed by Dave Johnson, P.E. :

32Khz Ultra Low Power Crystal Oscillator - I have used this circuit many times when I needed a low frequency reference, which did not draw much power.  With the components show, the current from a 3v battery is less than 1.2 microamps. . . Circuit by David A. Johnson P.E.-December, 2004

40Khz LED Test Signal Generator - This 40KHz crystal controlled oscillator circuit drives an infrared LED with powerful 40ma pulses.  The circuit can be used to test optical communications circuits, designed to receive 40KHz modulated light signals. . . Circuit by David Johnson P.E.-February, 2002

Crystal Controlled 1KHz Signal Generator - A while back I got an email from a Discover Circuits visitor.  He needed a way to calibrate a RPM display for a big diesel engine.  The engine had a tachometer output which produced 12 pulses per rotation with an amplitude of about 5v RMS.  The full scale reading on the engine’s RPM speed display dial was 5, 000. . . Circuit by David Johnson P.E.-May, 2012

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

LED Test Signal Generator-40Khz - This 40KHz crystal controlled oscillator circuit drives an infrared LED with powerful 40ma pulses.  The circuit can be used to test optical communications circuits, designed to receive 40KHz modulated light signals . . . Hobby Circuit designed by David A. Johnson P.E.-February, 2002


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

0.3V Crystal Oscillator with Buffered Output -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

0.5V Crystal Oscillator with Output Buffer -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

1 Second Time Base from Crystal Oscillator -  The schematic above illustrates dividing a crystal oscillator signal by the crystal frequency to obtain an accurate (0.01%) 1 second time base.  Two cascaded 12 stage counters (CD4040) form a 24 stage binary counter and the appropriate bits are gated together to produce the desired division.  Using a crystal of some even multiple of 2 is desirable so that one stage of the counter automatically toggles every second which eliminates the need for the NAND gate and reset circuitry, however the circuit below illustrates using a crystal which is not an even multiple of 2 and so requires additional __ Designed by Bill Bowden

10MHz GPS disciplined frequency standard -  This is the support page for the GPSDO described in the RSGB magazine RadCom for March 2008.  As this has become one of those never-ending projects, I have decided to start a web-page dedicated to this project and GPSDOs in general __ Designed by EI9GQ homebrew radio

32.768 kHz Oscillator using a Common Watch Crystal -  Below are a couple circuits you can use to produce a 32.768 KHz square wave from a common watch crystal.  The output can be fed to a 15 stage binary counter to obtain a 1 second square wave.  The circuit on the left using the 4069 inverter is recommended over the transistor circuit and produces a better waveform.  The single transistor circuit __ Designed by Bill Bowden

32 KHz Ultra Low Power Crystal Oscillator -  I have used this circuit many times when I needed a low frequency reference, which did not draw much power.  With the components show, the current from a 3v battery is less than 1.2 microamps. . . Circuit by David A. Johnson P.E.-December, 2004

4 Tone Audio Oscillator -  Schematic only - amateur radio construction project __ Designed by Peter Parker VK3YE

40 KHz LED Test Signal Generator -  This 40 KHz crystal controlled oscillator circuit drives an infrared LED with powerful 40ma pulses.  The circuit can be used to test optical communications circuits, designed to receive 40 KHz modulated light signals. . . Circuit by David Johnson P.E.-February, 2002

5 Hints for Debugging MicroController-based Designs an 1458 -  Application Note__ Aligent

A Crystal Heater construction project -  OK, here is the circuit I used - See image below.   The original National Semiconductor circuit had a 30 K resistor in series with a 400 µF cap., both in parallel with the 100 K resistor on the input of the 1st LM324 section.   I found that combo to actually destabilize the operation of the controller for this particular application, so I removed them & changed the 2 µF cap in series with the 10 Megohm resistor to 5 µF.__ Bob Dengler   NO6B

A Low-Frequency Crystal Controlled Oscillator -  The RF engineer sometimes has to look for an instrument that will check a low frequency quartz crystal unit reliably and rapidly.  This is a difficult piece of equipment to find and the engineer often has to consult an electronic circuits handbook for the schematic of a circuit that will perform the task.  Unfortunately __ Designed by Ramon Vargas

Crystal Considerations with Dallas Real-Time Clocks RTCS -  App Note #58__ Maxim Integrated

Crystal Controlled 1KHz Signal Generator -  A while back I got an email from a Discover Circuits visitor.  He needed a way to calibrate a RPM display for a big diesel engine.  The engine had a tachometer output which produced 12 pulses per rotation with an amplitude of about 5v RMS.  The full scale reading on the engine’s RPM speed display dial was 5, 000. . . Circuit by David Johnson P.E.-May, 2012

Crystal heater / temperature stabilization (TXCO) -  OK, here is the circuit I used - See image below.   The original National Semiconductor circuit had a 30 K resistor in series with a 400 µF cap., both in parallel with the 100 K resistor on the input of the 1st LM324 section.   I found that combo to actually destabilize the operation of the controller for this particular application, so I removed them & changed the 2 µF cap in series with the 10 Megohm resistor to 5 µF.__ Bob Dengler   NO6B

Crystal Oscillator overcomes typical Drawbacks -  08/17/98 EDN-Design Ideas - NOTE :  File has several circuits, scroll to this one.  Most crystal oscillators suffer from three drawbacks: They can't drive much of a load, the duty cycle isn't adjustable, and the duty cycle drifts.  The crystal oscillator in Figure 1 solves these problems.  Three parallel gates drive heavy loads, the duty cycle is adjustable from 25 to 75%; and feedback minimizes the drift. __ Circuit Design by Ron Mancini and Jeff Lies, Harris Semiconductor, Melbourne, FL

Crystal-Based 50 Hz Generator -  Here is a simple oscillator circuit that generates 50Hz frequency using a crystal.  It produces alternating 50Hz pulses with 50 per cent duty cycle, which can be used in inverter circuits....__ Electronics Projects for You

Crystal-Oscillator Is Ultralow Power -  EDN-Design Ideas -- 09/24/12    Build a crystal-oscillator circuit that draws only about 5 μA of current. __ Circuit Design by Thomas Mathews, Texas Instruments

Gated Crystal Oscillator with Very Low Power -  The circuit gates the output of a continuously operating 32 KHz 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

Harmonic VXO -  I needed a quick, very temperature + frequency stable oscillator @ 50.8 MHz to test a receive mixer.  Already running elsewhere on my bench, my main VHF signal generator wasn't an option. __ Contact Vasily Ivanenko

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.    __ Circuit Design by Adam Chen, Cypress Semiconductor, Woodinville, WA

LED Test Signal Generator-40Khz -  This 40 KHz crystal controlled oscillator circuit drives an infrared LED with powerful 40ma pulses.  The circuit can be used to test optical communications circuits, designed to receive 40 KHz modulated light signals . . . Hobby Circuit designed by David A. Johnson P.E.-February, 2002

Low Distortion Crystal Oscillator -  This crystal oscillator is designed to operate with fundamental crystals with less than 1 mW dissipated in the crystal.  The signal current is filtered by the crystal and develops a voltage across a capacitor with about 500 ohm of reactance.  The resulting sinewave has low distortion and phase noise.  A JFET  buffer is included to drive lower impedance loads.  Further buffering with an emitter follower and a  voltage step-down transformer or matching network is recommended for driving 50 ohm loads.  C3 may be reduced for larger output voltage or to allow lower drive level or it may be increased when lower output levels are desired __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Low-Frequency Crystal Controlled Oscillator -  The RF engineer sometimes has to look for an instrument that will check a low frequency quartz crystal unit reliably and rapidly.  This is a difficult piece of equipment to find and the engineer often has to consult an electronic circuits handbook for the schematic of a circuit that will perform the task.  Unfortunately __ Designed by Ramon Vargas


Oscillators:  Crystal Circuits     #'s - N        O - Z


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