How to build a variable frequency controler?

I am looking for advice. I need a varable control device that can take
standard 60 Hertz, 110 volts and give me a range from 15 Hertz to 200
Hertz at 110 volts. This will be used to adjust the frequency of
pulsating light given from a fluorescent light bulb. Some people find
reading difficulty under fluorescent light. My theory is that this may
be related to a sensitivity to the frequency. I have a basic knowledge
of what needs to be done, but I am not sure what components I need to
purchase and how to put them together. Any help will be appreciated!

 

[arem_29]

hi!.. i hope im not too late!...well, try to check this link,
http://www.tpub.com/electronics.htm
i think this might help you!...and i hope im right!...
i hope that helps!... bye!..til next time!




everymichael@msn.com wrote:

I am looking for advice. I need a varable control device that can take
standard 60 Hertz, 110 volts and give me a range from 15 Hertz to 200
Hertz at 110 volts. This will be used to adjust the frequency of
pulsating light given from a fluorescent light bulb. Some people find
reading difficulty under fluorescent light. My theory is that this may
be related to a sensitivity to the frequency. I have a basic knowledge
of what needs to be done, but I am not sure what components I need to
purchase and how to put them together. Any help will be appreciated!

 

[Roger Johansson]

John Fields wrote:

Since the inductive reactance of the
ballast is what limits the current through the lamp, and since
inductive reactance varies with frequency, I would expect the lamp to
dim if the input input frequency to the ballast was increased.

Yes, but that can be compensated by adjusting the voltage, using the
volume knob of the amplifier.

This would allow some experimenting with different frequencies, which
was the intent as I understood it.


--
Roger J.

 

[John Fields]

On 06 Jul 2005 04:47:00 GMT, "Roger Johansson" <no-email@no.invalid>
wrote:

John Fields wrote:

Since the inductive reactance of the
ballast is what limits the current through the lamp, and since
inductive reactance varies with frequency, I would expect the lamp to
dim if the input input frequency to the ballast was increased.

Yes, but that can be compensated by adjusting the voltage, using the
volume knob of the amplifier.

This would allow some experimenting with different frequencies, which
was the intent as I understood it.

---
I don't think anyone's questioning whether he could experiment or not,
I was just pointing out a possible pitfall.

--
John Fields
Professional Circuit Designer

 

[Tom LeMense]

John Fields wrote:

Since the inductive reactance of the
ballast is what limits the current through the lamp, and since
inductive reactance varies with frequency, I would expect the lamp to
dim if the input input frequency to the ballast was increased.

Yes, but that can be compensated by adjusting the voltage, using the
volume knob of the amplifier.

This would allow some experimenting with different frequencies, which
was the intent as I understood it.

---
I don't think anyone's questioning whether he could experiment or not,
I was just pointing out a possible pitfall.

Yes, certainly as the frequency is increased the voltage will 'droop'. I'd
attribute it to
hysteresis effects in the core, especially with the frequency >> 60 Hz.

If experiments didn't lead to more "pitfalls" they wouldn't be any fun,
right?

TJL

 

Roger Johansson wrote:

John Fields wrote:

Since the inductive reactance of the
ballast is what limits the current through the lamp, and since
inductive reactance varies with frequency, I would expect the lamp to
dim if the input input frequency to the ballast was increased.

Yes, but that can be compensated by adjusting the voltage, using the
volume knob of the amplifier.

This would allow some experimenting with different frequencies, which
was the intent as I understood it.


--
Roger J.

I think that inductive kick will blow up the audio amp. I had a friend
try this many years ago with MY amp. Never DID get around to fing the
old thing. What is wrong with using an electronic ballast? Or is this a
'I gotta know what frequency...'. I guess I'm just an old fart. The
solution is $25 at Lowes made by Osram.
GG

 

Roger Johansson wrote:

John Fields wrote:

Since the inductive reactance of the
ballast is what limits the current through the lamp, and since
inductive reactance varies with frequency, I would expect the lamp to
dim if the input input frequency to the ballast was increased.

Yes, but that can be compensated by adjusting the voltage, using the
volume knob of the amplifier.

This would allow some experimenting with different frequencies, which
was the intent as I understood it.


--
Roger J.

I think that inductive kick will blow up the audio amp. I had a friend
try this many years ago with MY amp. Never DID get around to fing the
old thing. What is wrong with using an electronic ballast? Or is this a
'I gotta know what frequency...'. I guess I'm just an old fart. The
solution is $25 at Lowes made by Osram.
GG

 

[Kubiack]

everymichael@msn.com a écrit :

I am looking for advice. I need a varable control device that can take
standard 60 Hertz, 110 volts and give me a range from 15 Hertz to 200
Hertz at 110 volts. This will be used to adjust the frequency of
pulsating light given from a fluorescent light bulb. Some people find
reading difficulty under fluorescent light. My theory is that this may
be related to a sensitivity to the frequency. I have a basic knowledge
of what needs to be done, but I am not sure what components I need to
purchase and how to put them together. Any help will be appreciated!

If the only thing you want to experiment is the light frequency, you
don't have to use a fluorescent light (witch is designed to operate at
50/60Hz).
You can build a very simple generator with a 0-5V 1Amp square output and
drive a series of white leds to illuminate what you want to illuminate.


On this other hand, if you really want to build a sine generator with a
110V output, you have a lot of work.
Such generators already exists and are used to drive asynchronous motors.