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MP
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Posts posted by MP
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Have you asked the author of the circuit?
http://www.redcircuits.com/
MP -
Interesting that you can read that into the data sheet when it is not there...
MP -
A 4047 oscillator makes a "squared-wave" signal like those others then divides it by 2 with a flip-flop so its outputs are exactly a square-wave, with a perfect 50-50 duty cycle. With just a single resistor and a single capacitor to set the frequency.
There is nothing in the datasheet that proclaims a "perfect 50-50 duty cycle. In fact, the manufacturer puts a disclaimer in the data sheet that a 50% duty cycle is not guaranteed. Fortunately, for a square wave inverter, you do not need a perfect square wave. You don't even need a perfect 50 hz or 60 hz. The square wave inverters are the worst of all inverters out there. You will see a large variance from one to the other. If you want to build something that will be useful, build a sinewave inverter.
MP
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Aren't we talking about an power inverter circuit, not just any oscillator?
Yes. I thought my answer was pretty clear in that regard.
MP
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defaced,
Your unloaded output voltage measurement is pretty meaningless. You need to measure the voltage loaded to get an accurate measurement. Also, if you want a well regulated 12 VDC supply, you should use a regulator. Most regulators require an input voltage which is 2 to 3 volts (or more) above the output voltage. Just get a 7812 voltage regulator for this power supply and you will have exactly what you need. If you use a transformer with an 8 volt secondary, you will not have enough voltage after loading occurs on the output.
MP -
Tkjas,
You seem to have quite an interest in Transformers. Here is a link about winding transformers. It might have some information in it that will prove to be useful to you.
http://geek.scorpiorising.ca/windingtransformers.html
MP -
Is the 4047 the only wat to make it? I mean are there any other techniques to produce AC, using transistors, etc.?
Many designs use Buffers, many use Inverters (NOT gates) to produce a nice square wave. I have also seen AND and NAND gates used to do this. Digital gates are good for providing a square wave. In fact, many circuit designs employ them to square up other wave forms that are not clean enough for a good digital switching action. The nice thing about using digital gates is that they have a good fan-out. Thus, you can parallel and/or series them to get a stronger signal if ever needed.
MP
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I have used the LM324 in many audio applications in the past. For the specifications that you have given, this chip will be fine. It will not give you really great results that you would get with a newer low noise op-amp. But it will give you a descent mixer. Especially at 1 KHZ.
MP -
The purpose of offset null is to compensate inconsistencies inside the op-amp that do not allow it to zero out when it should. It is not intended for the regulation of varying output loads. This is done through impedance and/or amplification methods. Perhaps I did not fully understand your post, but it does not sound like you are using the offset null correctly.
MP -
Hustla,
Welcome to the forum!
There is a circuit in the projects section of this site that might get you started, or at least, give you ideas on your own design. You can access the projects on this site with the blue link at the top of the page titled "Projects".
Hope this helps get you started.
MP -
As an aside, I've been investigating recharging regular, old alkaline batteries (I know, most think this is not a good thing) with this PS. In any event, I figure that capping the current at ~65mA and setting the voltage to the appropriate value for the cell I wish to charge, it may just work. What do you think?
I think that this is a different subject and should be discussed in it's own thread - not as an add-on to this thread...
MP
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I still see many posts each week that I have to move to the correct area.
This area is NOT for discussion of Projects you are looking for. It is NOT a general discussion area of Projects you have found somewhere on the web. It IS an area to discuss the Projects that are found on our website.
You can find these projects that are on our website by clicking on the blue link button titled "PROJECTS" near the top of the page.
MP -
Gogo,
You are correct. Rason's method will get the job done sufficiently. Try it on the workbench and you will see.
MP -
You are sending him away to Google? How rude!
Paris, Welcome to Electronics-Lab.
DAB is exactly what is says. It is a digital broadcast method for audio signals. I am sure you are looking for more regarding this than a definition, though. What information do you need, exactly. There are many experts on this site. I am sure someone can help you here in the Electronics-Lab Community.
MP -
Do you need 1 X 16? As mixos has published, 2X16 displays are fairly cheap. Also 4x20 display prices are not bad.
One thing that makes a big difference is which Continent you live on. You do not want to pay some of the high International shipping charges. Depending upon where you ship to, I have seen these get pretty ridiculous.
Earth LCD has a large selection. This is a US based company. You can find their prices at http://store.earthlcd.com
As an example, they have "Vikay 2035TNLD 2X16 Character Display for $7.00 each; Hantronix HDM20416L-1-L30F 4X20 Character Display for $25.00 each; Very popular Sharp LM24022 240X160 Graphic Display for $39.00 each.
Note: I am not affiliated with this company. Just a customer.
Also, if you can use a US based company, www.allelectronics.com has some of the best prices on LCDs in the world. 1X24 is $1.85, 240X64 at $11.00 each, etc.
Again, I must warn that these prices are pretty good as long as you don't add big shipping charges to them. Always calculate shipping charges when you are shopping around for an item.
MP -
Impossible to answer! Too many factors like percentage of area to be etched away, the type of pcb foil (20, 35, 70u), the solution you use, temperature and more.
Regarding ante's mention of solution, I wanted to add into the discussion that for safety, some etchants should not be heated. Some can be heated, but not above a certain temperature. This also depends upon the etchant used. Ferric Chloride, Ammonium Persulfate, Muriatic Acid, homebrew mix?
A little work in your pc board lab goes a long way. You should always dedicate a few boards to research and ruin them in a few tests that will give you benchmarks.
MP -
Thanks sarma,
I think we are already past this. It is good to have you back. Hope all is well.
MP -
There is another thread in this section (Projects Q/A) that is much longer. Some members did not want to go through that long thread and started this one. Unfortunately, some of the same questions are being asked here. I highly recommend that you read through the pages of the other thread. There you will find discussions of laying out the voltmeter and also comments about making it work with AC voltage.
MP -
I have had no luck in finding a metric horse ;D
MP -
you are probably right, ante...oops! I probably just fueled the fire with my last post ;D ...Couldn't help it. Had to say it.
MP -
MXR probably made the easiest one to copy. The SAD1024 might be a little hard to come by these days, but I know there are websites that carry this stuff. Let me know if you need help to find it.
Here is the schematic by MXR. Click on the link to get a better picture.
MP
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Sounds like we have very similar roots, ante! It's amazing how many guys in electronics started out in the music field.
You guys remember the Leslie Revolving speakers? Geez, I hated the sound of those things.
John, AG can't leave an argument without posting the last word. If you really want to move the theory part of the discussion to the theory area, you can split the post and move the part that turned into a theory discussion to the proper area.
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Hi Rod,
Glad to hear you are still here. As a new member, you might want to save the bag ante posted. You will need it from time to time... ;D ;D
It is true, however, that knowing your motor type is really needed to go on with a solution for you.
MP -
You can apply a higher voltage at the motors, connected to pins 2 and 7. Look at the data sheet I have attached for an example.
MP
VU meter
in Electronic Projects Design/Ideas
Posted
mik3ca,
Here is a standard circuit of vu meter that is made with transistors. Hope it helps.
MP