Need audio vco circuit

R

royalmp2001

Guest
I need a simple and cheap circuit for a voltage controlled oscillator
that will drive a small speaker with an audible tone. The voltage
range will be 0-1V from across a 1K resistor in another circuit.
Thanks
 
On 7 Mar 2005 08:08:23 -0800, the renowned "royalmp2001"
<royalmp2001@hotpop.com> wrote:

I need a simple and cheap circuit for a voltage controlled oscillator
that will drive a small speaker with an audible tone. The voltage
range will be 0-1V from across a 1K resistor in another circuit.
Thanks
Click to expand...
Assuming square wave or triangle will do you, check out the VCO
circuit on the LM324 datasheet. Can't get much cheaper/easier. If the
speaker is low impedance you'll need a buffer on the output, or if you
just need "audible", use a series resistor to knock the output current
down to single-digit mA.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
royalmp2001 wrote:

I need a simple and cheap circuit for a voltage controlled oscillator
that will drive a small speaker with an audible tone. The voltage
range will be 0-1V from across a 1K resistor in another circuit.
Thanks

http://www.ee.washington.edu/stores/DataSheets/linear/lm566.pdf
Click to expand...

that chip has been around all over.
check it out.
 
In article <1110211703.253669.177190@g14g2000cwa.googlegroups.com>,
royalmp2001 <royalmp2001@hotpop.com> wrote:
I need a simple and cheap circuit for a voltage controlled oscillator
that will drive a small speaker with an audible tone. The voltage
range will be 0-1V from across a 1K resistor in another circuit.
Thanks
Click to expand...
How about a CD4046?


--
--
kensmith@rahul.net forging knowledge
 
Sounds good, Ken...where can I find such a circuit?
 
royalmp2001 wrote:
Sounds good, Ken...where can I find such a circuit?
Click to expand...
You design it. The 555 has quite a bit if what you need, inside. It
has the threshold sensor and the discharge switch. You add a flip
flop to the pulse output to get a square wave. And you have to come
up with a variable current source to charge the capacitor that is
controlled by a second 555 oscillator to do the sweep. Hence the name
of this group. ;-)

--
John Popelish
 
In article <1110302074.221172.263590@z14g2000cwz.googlegroups.com>,
royalmp2001 <royalmp2001@hotpop.com> wrote:
Sounds good, Ken...where can I find such a circuit?
Click to expand...
Please explain "find such a circuit" in this context. Do you mean find a
CD4046? Do you mean find an existing application? Do you mean find a
schematic with part values?


--
--
kensmith@rahul.net forging knowledge
 
sorry, Ken
I mean what does the schematic look like. I'm no designer.
Thanks
 
In article <1110555862.049484.73120@f14g2000cwb.googlegroups.com>,
royalmp2001 <royalmp2001@hotpop.com> wrote:
sorry, Ken
I mean what does the schematic look like. I'm no designer.
Thanks
Click to expand...
Get a copy of the data sheet and app-notes for the CD4046 and read them,
ignoring the stuff about the phase detector and looking carefully at the
VCO section.


--
--
kensmith@rahul.net forging knowledge
 
"royalmp2001" <royalmp2001@hotpop.com> wrote:

sorry, Ken
I mean what does the schematic look like. I'm no designer.
Thanks
Click to expand...
Here's a practical circuit to get you started:
http://www.terrypin.dial.pipex.com/Images/4046VCO.gif

--
Terry Pinnell
Hobbyist, West Sussex, UK
 
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