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autir
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Posts posted by autir
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It's a programming tool too, Staigen.
Borland C++ Builder makes sure that you don't have to write code in order to create a button, window or similar graphical widget. You draw them on-the-fly using the appropriate tools. Like Visual Basic, if you have heard of.
Big deal.
Why;
Because the problem in our case is not whether the user interface will be hand-coded or drag-and-dropped. The problem is how to fit a C++ program containing graphics inside a microcontroller. No, better: the problem is how to convert a Win32 executable (possibly making use of Win32 API, due to graphics usage) to e.g. PIC16F84 machine code.
ECET0purdue:
Forgive me for asking or assuming things but it is impossible to know without asking.
You say you study ECE.
-> Have you completed cources dealing with computer architecture/ microcontrollers?
-> Have you completed cources dealing with embedded systems?
-> You know C++, so I assume that you know object-oriented programming concepts in general. Can you code in Java? -
Well, it doesn't sound easy. The touchscreen/interface part will be tricky.
Forget about C++. Most microcontrollers are programmed in assembly, lately there have appeared a small number of C and BASIC compilers. Why do you want C++ anyway? You cannot fit many objects inside a microcontroller... (needless to say that Borland C++ and similar compilers are out of the question) -
The solder wire is perfect 8)
It produces a very small amount of fumes, which do not smell at all. It does not "spit" burning hot drops all over my arms, and the solders are the shiniest I have ever done. A pleasant change from my old cheap solder wire. I have assembled my second circuit using this solder and a 25W Weller, and the results were more than perfect (for a person's second circuit, that is ;D )
I have read about the 63/37 chemical properties, and I will look if I can find something similar in the same brand / product line.
1st Mil-Tech, can I use alcohol for the cleaning of the PCB? audioguru said that the resin is water soluble and it may cause problems. -
An LM7912 doesn't make a negative supply, it is not a generator. It just regulates a negative supply that is already there. Its input voltage must be at least -15V for it to work perfectly. ::)
Darn... you are right... :-\
But I am sure I have seen a similar circuit in the LM7800 series datasheet. Producing negative voltage from an LM78xx. -
Will ordinary alcohol do? The one they sell in drug stores for medical reasons.
Isopropyl alcohol is full of or absorbs water, doesn't it? Keep away from it.
Care to explain this a little bit more? -
After reading some articles here regarding cleaning stripboards and PCBs after the soldering process, I went to a nearby paints store and asked for isopropyl alcohol or acetone. They only had acetone, of which the smallest container was a 1-liter metal vial. I bought one for 2.60 Euros. When I asked for small plastic bottles in order to use it in drops, the saleswoman replied that the acetone would dissolve the bottles rapidly. She added that this acetone was nothing like the ones used for nail polish removal. ALARM BELLS >:( . After returning home I studied the label on the container and it described all these nice things that can happen to my skin, eyes and lungs. Reading about acetone's chemical properties in the Web only made matters worse. So:
1) Have I bought the right type of acetone?
2) HOW ON EARTH am I going to use this... bomb in order to clear the flux remains on my solders and my stripboards/PCBs?
Thank you. -
Why not just use an LM7912?
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Jarmund hi
(familiar name... hmmm....) ::)
The typical solder we use today is an alloy of approximately 60% tin and 40% lead (Pb). This alloy has a low melting point (about 250 C ? ), so we are able to solder with ease and speed. Its only drawback is that lead is an extremely poisonous substance. After the summer of 2006 solder material on sale will be required to be absolutely pb-free. It will have a higher melting point, thus resulting in more "cold" solders, damaged ICs (from the extra heat required to make the solder), etc. Not to mention that the new alloys will contain a small percentage of silver, so their value will be much higher. -
Audioguru hi :)
The 0.5 kg package costs 10 Euros. I do not know if it is expensive or not, it is the first time I buy solder wire in a large quantity.
It does not seem to be much money because it will last me months. The time needed to correct wrong solders (my soldering skills are still low) is worth it.
Should I stock on this specific quality? Is its only drawback that the solders conduct in high humidity? Will it be ok for circuits which are going to stay indoors? Can't I insulate the board with the special enamel spray afterwards?
What is this "no clean" feature anyway? ??? -
Thank you for your answers. :)
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There isn't a problem attaching ICs or transistors without insulators to a heatsink when their cases or tabs have the same voltage. Each one should be wired separately because they make a lousy electrical connection to the heatsink.
What do you mean "wired seperately"?
If there is a resistor an the tab of the TO-220s and the heatsink is soldered to the neutral of the board, won't we have unwanted current flowing through the heatsink?
So you propose that the best place for an ammeter in this circuit is the one in the picture?
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Can a solder wire be both "no clean" and "rosin cored"?
I have read on some articles in the Internet that "no clean" solder wire must be avoided at all costs. Why could make them say it? -
Guys? ::)
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What is no-clear, rosin-based etc. flux?
Are there types of flux which are corrosive and must be avoided at all costs? If so, why are they in production?
What should we pay attention to when buying solder wire?
Ok, here goes a specialised question -
It works. Perfect :D
It was the unshielded copper wire which, in conjuction with the thousands :P of crocodile clips, caused the hum.
I put it in a box and added all the necessary connectors.
One of these days I'm going to borrow a digital camera from a friend and take some snapshots.
Audioguru, thanks. Without your help this would not have been possible.
:D -
It worked!
I attached the power resistor directly to the breadboard and measured the voltage across its ends. It was 4.87V, dropping as the IC began to heat up and became stabilised at 4.78V.
In the lab I've attended we were used to work with external and/or PSU ammeters + voltmeters, plus a net of cables with banana clips. So much for old habits ;)200uF is too small for much output current
Typo. It is 2200uF :)The IC has a small resistance in the metal of the tab and between its ground pin and the tab.
Can I attach many ICs in the same heatsink without problems such as short-circuit? (with all tabs being ground, of cource.)inside the regulator's negative feedback loop
What/where is that? :)It is better between the rectifier and the 200uF (200uF is too small for much output current), then the input voltage of the IC will be more steady when the load changes.
Won't the analog ammeter's coil be damaged by the unregulated DC passing through?
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Click on the "Search" button :D
http://www.electronics-lab.com/forum/index.php?action=search -
a heavy copper trace on its pcb
Can't I build it on stripboard? :-\Its heatsink tab should measure very close to 0V but its heatsink makes poor electrical contact through the thermal grease.
Why very close to and not exactly 0 V? I have not used thermal paste yet.You shouldn't use an ammeter in series with the load.
I have seen PSUs which had ammeters and voltmeters. How do they do it?
I thought I should install an ammeter in order to monitor the power consumption of my circuits. It is supposed to be connected between the 200uF's "+" and the 330nF's "live" connections, is this the correct location?The ammeter has a voltage drop which reduces the voltage across the load (and therefore reduces the current through the load).
No offence, but isn't the ammeter's resistance supposed to be too small to produce more than the slightest voltage drop?
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I think the circuit's R1 should be adjusted to match the supply voltage. The FET inside an electret mic draws about 500uA, so in order to have half the supply voltage across it then for a 3V supply, R1 should be about 3k ohms, for a 9V supply R1 should be about 9k ohms and for a 12V supply R1 should be about 12k ohms.
Can you explain this a little bit more? :-[ ;DIt is best to measure it
How? As a resistor?Its Zout is in parallel with its load/supply resistor (R1 in your circuit).
Isn't Zout=R2//R1//Zmic ?
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A big mistake from my part: Whenever you saw "power ground" in my last two posts, read "power neutral" instead. So the neutral cable of the LM7805 is connected (via capacitors, circuit etc.) both to my PC line-out ground and to the output speakers' ground. I have not grounded my LM7805's circuit.
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Hi Autir,
This topic is never dead! -
Something is wrong
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Which version of Multisim is newer? 7 or 2001 ?
My new project
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