Adjusting frequency NE556

  • Thread starter Dave, I can't do that
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Dave, I can't do that

Guest
Hi,

The following is a PDF of a motor control kit...

http://www.electronickits.com/kit/complete/motor/ck1400.pdf

Currently it is designed to run at around 410Hz.

I assume that too will be the frequency for the PWM output but I need
5KHz from the PWM.

I looked at the formula for frequency on page 1 and it may as well be
written on Chinese as far as I can tell.

Could someone with a brain significantly superior to mine, please tell
me what components need to be changed to get this to operate at 5Kz. I
need this to operate at 5KHz, 5volts and 100mA PWM output from 0%-95%

Thanks so much.

Dave
 
On 2008-09-17, Dave, I can't do that <davenpete@gmail.com> wrote:
Hi,

The following is a PDF of a motor control kit...

http://www.electronickits.com/kit/complete/motor/ck1400.pdf

Currently it is designed to run at around 410Hz.

I assume that too will be the frequency for the PWM output but I need
5KHz from the PWM.
Click to expand...
R3 R4 and C2 control the rate of the PWM

as you want it to run about 12 times faster you need to decrease the
capacitor (C2) or the resistors (r3,r4) by a factor of 12.

I'd replace C2 with an 8.2nF capacitor which should get you fairly
close to 5Khz, (if a more precise 5khz is needed also replace r3 with a 27K with
a 10K trimmer in series.)

C6 and r5 are also responsible for the on-time of the pulses and
one of those should also be adjusted down by a factor of 12 (probably
easiest to change the capacitor again)

there is a different, simpler, PWM cricuit (that works well especially
if precise control or stability of the frequency is not needed) that
uses just a single 555 (or half of a 555) and places the variable
resitance with a pair of steering diodes inside the oscillator circuit.

Bye.
Jasen
 
Thanks Jasen and Jerry, I will give them a try.

Dave
 
Jasen Betts wrote:
On 2008-09-17, Dave, I can't do that <davenpete@gmail.com> wrote:

Hi,

The following is a PDF of a motor control kit...

http://www.electronickits.com/kit/complete/motor/ck1400.pdf

Currently it is designed to run at around 410Hz.

I assume that too will be the frequency for the PWM output but I need
5KHz from the PWM.


R3 R4 and C2 control the rate of the PWM

as you want it to run about 12 times faster you need to decrease the
capacitor (C2) or the resistors (r3,r4) by a factor of 12.

I'd replace C2 with an 8.2nF capacitor which should get you fairly
close to 5Khz, (if a more precise 5khz is needed also replace r3 with a 27K with
a 10K trimmer in series.)

C6 and r5 are also responsible for the on-time of the pulses and
one of those should also be adjusted down by a factor of 12 (probably
easiest to change the capacitor again)

there is a different, simpler, PWM cricuit (that works well especially
if precise control or stability of the frequency is not needed) that
uses just a single 555 (or half of a 555) and places the variable
resitance with a pair of steering diodes inside the oscillator circuit.

Bye.
Jasen
And then again, you can use a dual comparator/op-amp, one unit as the
Click to expand...
triangle wave generator while the other is used as the comparator.
With the above, you can obtain 0..100% PWM at what ever the triangle
wave is set for with out screwing with duty cycle factors.

http://webpages.charter.net/jamie_5"
 
On Thu, 18 Sep 2008 17:47:04 -0400, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

Jasen Betts wrote:
On 2008-09-17, Dave, I can't do that <davenpete@gmail.com> wrote:

Hi,

The following is a PDF of a motor control kit...

http://www.electronickits.com/kit/complete/motor/ck1400.pdf

Currently it is designed to run at around 410Hz.

I assume that too will be the frequency for the PWM output but I need
5KHz from the PWM.


R3 R4 and C2 control the rate of the PWM

as you want it to run about 12 times faster you need to decrease the
capacitor (C2) or the resistors (r3,r4) by a factor of 12.

I'd replace C2 with an 8.2nF capacitor which should get you fairly
close to 5Khz, (if a more precise 5khz is needed also replace r3 with a 27K with
a 10K trimmer in series.)

C6 and r5 are also responsible for the on-time of the pulses and
one of those should also be adjusted down by a factor of 12 (probably
easiest to change the capacitor again)

there is a different, simpler, PWM cricuit (that works well especially
if precise control or stability of the frequency is not needed) that
uses just a single 555 (or half of a 555) and places the variable
resitance with a pair of steering diodes inside the oscillator circuit.

Bye.
Jasen
And then again, you can use a dual comparator/op-amp, one unit as the
triangle wave generator while the other is used as the comparator.
With the above, you can obtain 0..100% PWM at what ever the triangle
wave is set for with out screwing with duty cycle factors.
Click to expand...
---
sci.electronics.basics, ain't it?

It'd be nice if you'd post a link to a schematic or a schematic instead
of just mouthing off, trying to convince everyone how smart you are.

JF
 
Jamie wrote:
Jasen Betts wrote:

On 2008-09-17, Dave, I can't do that <davenpete@gmail.com> wrote:

Hi,

The following is a PDF of a motor control kit...

http://www.electronickits.com/kit/complete/motor/ck1400.pdf

Currently it is designed to run at around 410Hz.

I assume that too will be the frequency for the PWM output but I need
5KHz from the PWM.



R3 R4 and C2 control the rate of the PWM
as you want it to run about 12 times faster you need to decrease the
capacitor (C2) or the resistors (r3,r4) by a factor of 12.

I'd replace C2 with an 8.2nF capacitor which should get you fairly
close to 5Khz, (if a more precise 5khz is needed also replace r3 with
a 27K with
a 10K trimmer in series.)

C6 and r5 are also responsible for the on-time of the pulses and one
of those should also be adjusted down by a factor of 12 (probably
easiest to change the capacitor again)

there is a different, simpler, PWM cricuit (that works well especially
if precise control or stability of the frequency is not needed) that
uses just a single 555 (or half of a 555) and places the variable
resitance with a pair of steering diodes inside the oscillator circuit.

Bye.
Jasen

And then again, you can use a dual comparator/op-amp, one unit as the
triangle wave generator while the other is used as the comparator.
With the above, you can obtain 0..100% PWM at what ever the triangle
wave is set for with out screwing with duty cycle factors.

http://webpages.charter.net/jamie_5"

And to add to my post since JF got so sentimental about it.
Click to expand...

http://www.4qdtec.com/pwmmod.html

The above can be replaced with a comparator or
op-amp that employs the totem pole outputs. Meaning,
they source and sink on the output. This can eliminate
the need for the high side R that is being used now since
the LM339 id open collector on the outputs.

Personally, I would use a LM358 or something in that line
which is what I normally use..

Many others will work of course, that is just an example.

And John, I don't have time to translate schematics to ASCII
art because I would have to do so by hand.




http://webpages.charter.net/jamie_5"
 
On Thu, 18 Sep 2008 21:41:34 -0400, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

Jamie wrote:
Jasen Betts wrote:

On 2008-09-17, Dave, I can't do that <davenpete@gmail.com> wrote:

Hi,

The following is a PDF of a motor control kit...

http://www.electronickits.com/kit/complete/motor/ck1400.pdf

Currently it is designed to run at around 410Hz.

I assume that too will be the frequency for the PWM output but I need
5KHz from the PWM.



R3 R4 and C2 control the rate of the PWM
as you want it to run about 12 times faster you need to decrease the
capacitor (C2) or the resistors (r3,r4) by a factor of 12.

I'd replace C2 with an 8.2nF capacitor which should get you fairly
close to 5Khz, (if a more precise 5khz is needed also replace r3 with
a 27K with
a 10K trimmer in series.)

C6 and r5 are also responsible for the on-time of the pulses and one
of those should also be adjusted down by a factor of 12 (probably
easiest to change the capacitor again)

there is a different, simpler, PWM cricuit (that works well especially
if precise control or stability of the frequency is not needed) that
uses just a single 555 (or half of a 555) and places the variable
resitance with a pair of steering diodes inside the oscillator circuit.

Bye.
Jasen

And then again, you can use a dual comparator/op-amp, one unit as the
triangle wave generator while the other is used as the comparator.
With the above, you can obtain 0..100% PWM at what ever the triangle
wave is set for with out screwing with duty cycle factors.

http://webpages.charter.net/jamie_5"

And to add to my post since JF got so sentimental about it.

http://www.4qdtec.com/pwmmod.html

The above can be replaced with a comparator or
op-amp that employs the totem pole outputs. Meaning,
they source and sink on the output. This can eliminate
the need for the high side R that is being used now since
the LM339 id open collector on the outputs.

Personally, I would use a LM358 or something in that line
which is what I normally use..

Many others will work of course, that is just an example.

And John, I don't have time to translate schematics to ASCII
art because I would have to do so by hand.
Click to expand...
---
Who gives a shit?

JF
 
John Fields wrote:

On Thu, 18 Sep 2008 21:41:34 -0400, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:


Jamie wrote:

Jasen Betts wrote:


On 2008-09-17, Dave, I can't do that <davenpete@gmail.com> wrote:


Hi,

The following is a PDF of a motor control kit...

http://www.electronickits.com/kit/complete/motor/ck1400.pdf

Currently it is designed to run at around 410Hz.

I assume that too will be the frequency for the PWM output but I need
5KHz from the PWM.



R3 R4 and C2 control the rate of the PWM
as you want it to run about 12 times faster you need to decrease the
capacitor (C2) or the resistors (r3,r4) by a factor of 12.

I'd replace C2 with an 8.2nF capacitor which should get you fairly
close to 5Khz, (if a more precise 5khz is needed also replace r3 with
a 27K with
a 10K trimmer in series.)

C6 and r5 are also responsible for the on-time of the pulses and one
of those should also be adjusted down by a factor of 12 (probably
easiest to change the capacitor again)

there is a different, simpler, PWM cricuit (that works well especially
if precise control or stability of the frequency is not needed) that
uses just a single 555 (or half of a 555) and places the variable
resitance with a pair of steering diodes inside the oscillator circuit.

Bye.
Jasen

And then again, you can use a dual comparator/op-amp, one unit as the
triangle wave generator while the other is used as the comparator.
With the above, you can obtain 0..100% PWM at what ever the triangle
wave is set for with out screwing with duty cycle factors.

http://webpages.charter.net/jamie_5"


And to add to my post since JF got so sentimental about it.

http://www.4qdtec.com/pwmmod.html

The above can be replaced with a comparator or
op-amp that employs the totem pole outputs. Meaning,
they source and sink on the output. This can eliminate
the need for the high side R that is being used now since
the LM339 id open collector on the outputs.

Personally, I would use a LM358 or something in that line
which is what I normally use..

Many others will work of course, that is just an example.

And John, I don't have time to translate schematics to ASCII
art because I would have to do so by hand.


---
Who gives a shit?

JF
Most likely no one John! But then again, you should know how that
Click to expand...
feels.

http://webpages.charter.net/jamie_5"
 
On Fri, 19 Sep 2008 18:26:36 -0400, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

And John, I don't have time to translate schematics to ASCII
art because I would have to do so by hand.


---
Who gives a shit?

JF
Most likely no one John! But then again, you should know how that
feels.
Click to expand...
---
Why?

I don't whine about why I can't do ASCII art, I just do it.


JF
 
John Fields wrote:
On Fri, 19 Sep 2008 18:26:36 -0400, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

And John, I don't have time to translate schematics to ASCII
art because I would have to do so by hand.


---
Who gives a shit?

JF
Most likely no one John! But then again, you should know how that
feels.

---
Why?

I don't whine about why I can't do ASCII art, I just do it.
Click to expand...

Isn't it amazing that a 'programer' can't write a little coherent
text?


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
 
On Fri, 19 Sep 2008 19:40:38 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

John Fields wrote:

On Fri, 19 Sep 2008 18:26:36 -0400, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

And John, I don't have time to translate schematics to ASCII
art because I would have to do so by hand.


---
Who gives a shit?

JF
Most likely no one John! But then again, you should know how that
feels.

---
Why?

I don't whine about why I can't do ASCII art, I just do it.


Isn't it amazing that a 'programer' can't write a little coherent
text?
Click to expand...
---
Some can. :)

Look at Larkin.

He's basically a hardware guy who programs in assembler for the joy of
it, and so am I.

Not that I'm allying myself with him, but I think, as programmers, we
both post coherent text.

JF
 
John Fields wrote:
Michael A. Terrell wrote:

Isn't it amazing that a 'programer' can't write a little coherent
text?

Some can. :)

Look at Larkin.

He's basically a hardware guy who programs in assembler for the joy of
it, and so am I.

Not that I'm allying myself with him, but I think, as programmers, we
both post coherent text.
Click to expand...

I agree, but neither of you had a sig file bragging about your
programing skills. You just do it. :) You two have different styles,
but are doing the work, rather than bragging and pointing to a crude
'brag' website.

I used to write software but with my failing eyesight, it's just too
much trouble to only be able to work for about fifteen minutes a day,
and end up with a headache. Hopefully, I'll finish some modifications
to my house before winter, and have room for the 22" monitor again. I
need to sit about 12 inches from it, and use a larger font than I used
to. I used to have about 90 lines of text on the screen when writing
code. No more. :(

The project I need to finish is a EEPROM reader for video monitors, to
see what modes they are capable of without connecting them to a
computer.



--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
 
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