Hi.
i want to get more power out of a software signal generator that outputs through the soundcard.
A couple of questions :
1. Would i just use a transistor (2N3055 ?) hooked up to a DC power supply ?
2. Would there be any frequency interference from the DC PSU ?
Thanks,
Gary.
Quote from: DeepCut on November 28, 2010, 10:18:49 AM
Hi.
i want to get more power out of a software signal generator that outputs through the soundcard.
A couple of questions :
1. Would i just use a transistor (2N3055 ?) hooked up to a DC power supply ?
2. Would there be any frequency interference from the DC PSU ?
Thanks,
Gary.
That will not work, at least not easily.
The simplest thing for you to do imo would be to find and audio amplifier of some sort...any type with an input for audio sources will do, depending on how much power you want out.
Run the soundcard output straight into the audio amplifier input, and start with the soundcard output level almost at zero. You can incorporate an attenuator pot if you wish to cut the level down, but it's most likely not necessary.
.99
Thanks poynt,
i tried that with a mono mic preamp i had lying around.
The meter sees the voltage going high/low so it's working.
But i want to use my DC PSU so i know the voltage/current going in and use the full range of the PSU.
I thought i could modify a spare Bedini circuit i had, since it does exatly what i need, a small trigger voltage causing the larger PSU voltage to flow.
But i can't seem to be able to do it :(
Gary.
If you are looking to be able to monitor how much power is being used from a power supply, then you might be interested in a small amplifier module such as this one on ebay:
http://cgi.ebay.ca/Low-Voltage-Audio-Amplifier-Module-Based-NJM386-/400176660727?pt=LH_DefaultDomain_0&hash=item5d2c6340f7
Might be just what you require ;)
.99
@deepcut,
I agree with poynt99...It would be best to get some audio amplification
before driving a 2n3055 NPN power transistor base circuit. A "standard
audio line" such as the output of a computer is meant for driving earphones
or (stereo) amplifier inputs.
"Standard audio line" has the 0db point at 1 volt peak-to-peak into 600ohms
where the center voltage is ground/0volts. So I would expect a computer
with it's volume set 1/2 way up to be issuing standard audio line output power.
A standard audio line is what a TV set might have when it knows it is going to
be driving a amplifier to a speaker. While standard line level is what the amplifier
input will expect to see. Audio speakers have relatively low impedance like 4 to 64
ohms so they are power devices.
The standard line may be just able to drive the 2n3055 if you use an audio isolation
transformer. - Like the phone line transformer from an old obsolete modem card.
Those are often primary 600ohms:600ohms secondary that is 1:to:1. Obviously a
2n3055 is going to produce a unipolar (digital) signal of swing +V to 0. An audio
amp preserves the +V to -V swing of the signal. Use a transformer or blocking
capacitor to get the signal polarity of AC signal you want.
Any out-of-band-noise can be filtered with a small (filter) cap.
:S:MarkSCoffman
Using a 2N3055 alone to make an audio amplifier would be a tricky proposition (esp. for those not familiar with discrete analog design), which is why I mentioned that it would not be easy.
Unless I don't understand your requirements, going with an amp module (similar to above) is a far better solution imo.
.99
Thanks mark and poynt, perhaps an audio amp is the way to go i'm not sure.
All i want to do is pulse a coil from my PSU, using the software signal generator as a trigger.
This is exactly what Bedini's SSG circuit does except the magnets are the trigger, inducing a voltage into the trigger wire that allows the power to flow from the PSU.
I will try an amplifier today i have a little PC one somewhere.
Thanks again for the help,
Gary.
Quote from: DeepCut on November 29, 2010, 07:02:40 AM
Thanks mark and poynt, perhaps an audio amp is the way to go i'm not sure.
All i want to do is pulse a coil from my PSU, using the software signal generator as a trigger.
This is exactly what Bedini's SSG circuit does except the magnets are the trigger, inducing a voltage into the trigger wire that allows the power to flow from the PSU.
I will try an amplifier today i have a little PC one somewhere.
Thanks again for the help,
Gary.
OK, now I think I understand. That is a bit different. I thought you wanted to amplify analog signals, but a trigger is what you are really after. The amplifier module will probably still work for this purpose, but use it to drive your 2N3055.
All you really need is to amplify the current drive to the 2N3055, and for this you could use a 2N3904 in front of it as a Darlington pair. This will still allow you to power off your supply and pulse the coil as required. Fairly simple.
If you understand great, if not let me know and I can draw something up.
.99
Thanks a lot poynt, i'm off to maplins to grab a 3904.
If you have the time i'd really appreciate if you could draw something up, i've googled darlington pair but i'm not so sure about the overall circuit.
Yesterday i was playing with a 3055 and couldn't even get a CE output voltage with 9V at the base ? Maybe i don't understand transistors properly yet, i'm fairly new to this and still learning.
Thanks again,
Gary.
Damn !
Two branches of my electronics store and both out of 3904's :(
I've got two 3055's, gonna give it a try with those.
Gary.
There are many small signal high voltage NPN transistors that would do the job. The 2N3904 is probably not the best choice here anyway with its relatively low VCE of 40V.
I might try the MPS8099, as it has a VCE of 80V, similar to the 2N3055. If you are not using a flyback diode across the coil, be sure to use protection across the transistor C-E so as not to exceed the VCE rating. Bedini uses neon bulbs, but they fire at about 90V if I am not mistaken.
.99
@deepcut
Sometimes the simplest answer is the best one, buy a set of cheap computer headphones then cut one of the speakers off and glue it onto the other one so they are facing one another with a spacer tube between them. When the output speaker from your computer moves the speaker you just glued onto it must move with it and acts as an AC generator, a coil moving in relation to a magnet. Use a signal diode off the second speaker to produce a DC output which can be used to energize a signal transistor or mosfet. Now this may seem rather crude but it does one thing exceptionally well, it offers a means of complete electrical isolation as the energy transfer media is air between the speakers. If you are triggering HV impusive currents it is only a matter of time before a HV transient wipes out your electronics, your sound card and possibly the motherboard of your computer through the most unlikely of paths and this simple system will protect your computor like few other circuits can. I have seen 1/2" arcs across isolation transformers which have wiped out my triggering electronics and they will also wipe out most all other electronics within the common ground path. In fact some of my circuits have produced violent cracking noises inside my old oscilloscope a few feet away when the scope leads were not attached to anything which was a little scary,lol.
Regards
AC
Here is something that should get you in the ballpark.
Neon2 is an extra line of protection for your PC or generator in case Neon1 does not fire. I would also recommend incorporating the flyback diode, unless the design calls for this being absent.
.99
@allcanadian
Is this what you mean?
Thanks AC that's a highly-inventive solution. I'm not yet using HV but when i do i'll remember your post.
.99 thanks very much for that, i'll set it up tomorrow and tell you how it went.
Thanks again,
Gary :)
One other method to isolate your PC from the equipment is to use a sound-cart with an optical out, and a amplifier with an optical in.
I think you can buy those relatively cheap second hand.
Ahh, nice idea, thanks Cherry.
Gary.
@nievesoliveras
Yes, that looks ok only I used a 3 inch piece of plastic pipe as a spacer between the speakers for a larger seperation. The inner pipe and speakers are basically air tight so that any motion from one speaker must move the other like pistons in a cylinder.
Regards
AC
@DeepCut
When I want audio output using my software frequency generator, I have my computer sound card that goes into a small 4 channel mixer that has a small amplification ability since it has to be plugged into the wall socket.
Then I have a stereo jack that goes into the mixer headphone output that I can control with volume and balance control.
The software for audio frequencies I use is located on my ftp site here;
http://purco.qc.ca/ftp/Software/frequency-generator/
With this software you can use left or right or both and even adjust phase. If you want to feed more frequencies then two, just open the software again and again for as many as you want. You can go as high as 20kHz with this software.
You should be able to buy a small mixer in a pawn shop for real real cheap. Mine is a Eurorack UB1002.
This way, whatever I do will never go back to the computer sound card because my sound card is pretty expensive made by M-Audio model Audiophile 2496.
I even put the left and right positives together and the commons together to pulse a small coil directly. Some of my tests I do not even use a mosfet.
Hi wattsup,
I'll take a look at your software it sounds good thanks for link.
i use this software, the f-gen goes up to 10Khz plus it has oscilloscope, frequency analysis ... :
http://www.zeitnitz.de/Christian/scope_en
The idea of a little mixer is nice. My soundcard is a Terratec DMX 6 fire so i don't want to hurt that, just like you :)
I was thinking of getting this pre-built PWM :
http://www.rmcybernetics.com/shop/cyber-circuits.htm#A21
The first one on the page.
It seems to have good features but only goes up to 1.5MHz, what do people think of it ?
Gary.
Seems like it does not consume that much to run it so that is good. And the throughput is 9A-400V up to 1.5mhz so it could be used as an inline to loop many pulsing schemes where you start with a battery feed inline at lower levels and let the circuit grow in gain.
I always ask myself what am I willing to blow up in a test.
For sound cards, now that I think of it, I could add a second sound card to have two more channels. I would have A with L/R and B with L/R. Then I could play around with three and four. I could use all four channels of my mixer and pan them full left or right or even use four splitters, one per channel.
Ye i looked up your mixer, it's a nice unit.
Check out my latest test results :
http://www.overunity.com/index.php?topic=10077.new;topicseen#new
Gary.