All About Circuits Forum  

Go Back   All About Circuits Forum > Electronics Forums > The Projects Forum


The Projects Forum Working on an electronics project and would like some suggestions, help or critiques? If you would like to comment or assist others with their projects, this is the place to do it.

Reply   Post New Thread
Thread Tools Display Modes
Old 09-21-2009, 01:49 AM
gagan gagan is offline
New Member
Join Date: Sep 2009
Posts: 2
Default Variable frequency sine wave

hey guys. I want to build a variable frequency sine wave generator with a constant amplitude. any suggestions??

Reply With Quote
Old 09-21-2009, 01:54 AM
Audioguru Audioguru is offline
Join Date: Dec 2007
Location: Ontario, Canada
Posts: 9,411

A Wien Bridge oscillator using a light bulb or a Jfet for amplitude stabilization works well.
Mine goes from 10Hz to 100kHz.
Reply With Quote
Old 09-21-2009, 02:30 AM
gagan gagan is offline
New Member
Join Date: Sep 2009
Posts: 2

hey thanks for the quick reply

I'm considering the following circuit
Figure 1 Easily tuned sine wave oscillator

Can any one help me by explaining what exactly how sine wave is being genrated in the circuit.

Audioguru:- I did consider wien bridge option but can't figure out how to control the amplitude using jfet exactly. If you could explain a bit more on that part, then it will be great.

Reply With Quote
Old 09-21-2009, 10:03 PM
Bill_Marsden's Avatar
Bill_Marsden Bill_Marsden is offline
Super Moderator
Join Date: Mar 2008
Location: Dallas, TX (GMT-5 w/ DST)
Posts: 19,022
Blog Entries: 5

How pure does this sine wave have to be? If the answer is not extremely, then you can use other methods.

To answer your question the Zeners clip the wave form, leaving what is effectively an active filter to clean up the harmonics.
"Good enough is enemy of the best." An old engineering saying, Author unknown.

General info:
If you have a question, please start a thread/topic. I do not provide gratis assistance via PM nor E-mail, as that would violate the intent of this Board, which is sharing knowledge ... and deprives you of other knowledgeable input. Thanks for the verbage Wookie.
Reply With Quote
Reply   Post New Thread

, , ,

Related Site Pages
Section Title
Worksheet Phase-locked loops
Worksheet Opamp oscillator circuits
Worksheet Performance-based assessments for semiconductor circuit competencies
Worksheet Signal modulation
Worksheet Oscillator circuits
Worksheet Junction field-effect transistors
Worksheet AC network analysis
Worksheet Passive integrator and differentiator circuits
Worksheet Mixed-frequency signals
Textbook Square wave signals : Mixed-frequency Ac Signals

Similar Threads
Thread Thread Starter Forum Replies Last Post
help building a variable sine wave generator pkennedy The Projects Forum 37 05-06-2010 03:54 AM
sine wave shaper lalalu Homework Help 16 11-26-2009 05:05 AM
Square wave to sine wave JBmtk General Electronics Chat 4 07-15-2009 05:14 PM
matlab - finding amplitude, frequency & periodic time of given sine wave wick54 Programmer's Corner 7 03-28-2009 12:26 AM
variable frequency power supply relicmarks General Electronics Chat 17 11-18-2008 09:39 PM

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT. The time now is 03:42 AM.

User-posted content, unless source quoted, is licensed under a Creative Commons Public Domain License.
Powered by vBulletin
Copyright ©2000 - 2014, vBulletin Solutions, Inc.