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MP
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Posts posted by MP
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I think Orcad has a place on their website where if you register, you can draw and view files using the software on their website without a charge.
You should be able to view a postscript file with Adobe pdf reader. Ghostview is another free program that will allow you access to postscript files.
MP -
...almost everything on the motherboard of the computer you typed that on is static sensitive... ;D
Just a little humor there.
MP -
siddharth, my comment on not wanting to pop anyone's bubble was only in reference to a post recomending a transistor which was not the same type as on the data sheet (NPN vs PNP).
You were on the right track to begin with. The one you posted and the data sheet. There are probably thousands of ways to do this and they will all work.
I really enjoy it when someone posts a circuit and asks for ideas regarding it. What really frustrates me is when several people jump in and try to talk them into doing it a different way with no additional information causing them to believe the circuit will not work. Why change your design because someone else does not do it that way? Then comes the confusion. By the way, in your posted schematic with NPN, you can use 2N3904. In the data sheet schematic with PNP you can use a 2N3906. These are not the only transistors that you can use, but they are very common.
I hope you decide on a circuit for your project soon.
MP -
Pins 15 and 16 are for your backlight on some display types and they are on the side with a couple of characters like K and L or + and -. Also, the voltage needed for the backlight might be +5 volts or -15 volts or anything in between. Different manufacturers use different voltages for the backlight. The first page of the projects advises you to get familiar with your display data sheet. This is because there are more types of displays out there than there are color TV manufacturers. They all have their own way of doing things.
From your data sheet: What voltage does your particular display need to run the backlight? You will need to substitute this voltage for the +5V listed in the project. Where does it suggest you connect the wires?
If your display does not have a backlight circuit, you might be sending voltage to components on the display's circuit board which are causing this problem.
Everything you need to know is in the data sheet for your display. If you do not have a data sheet for the display, you can post a request in the data sheet request area on this site. Someone in this community probably has it or has seen it.
If you are in a hurry, just disconnect pins 15 and 16 and go on with the project. You will still be able to see the characters. Just not as well.
Also, I am just curious about something. What software will you be using to run the display?
MP -
Mikail, measure the resistance of each winding. This will give you the ratio. Use the basic formulas for transformers to go from there. DO NOT connect this transformer to mains until you know that it is the correct type of transformer.
Be safe!
MP -
sure, try connecting a 9 volt battery to a 7805 regulator and see how long your battery lasts...
Half of the voltage is converted to heat at the ground tab. It is not converted to current. It is only converted to loss. The more voltage you have to drop, the worse the problem. Regulators are not always the answer and should not be the first word spoken when someone needs to reduce the voltage. Other alternatives also exist and the function of the circuit must be considered first.
This zener vs regulator discussion is meaningless.
MP -
Some manufacturers made 16 X 1 displays which were 16 characters on one line, but the on-board electronics were actually 8 X 2. These were referred to as 16X1a.
MP -
Serge, I am assuming that you have built this circuit and it is working good, yes?
MP -
As AVRFreakMan has said...check out the link.
MP -
juanpmoron, C7 is just a bypass cap on the output. Most likely, you have either connected it wrong or you are using a capacitor with too low of a voltage rating. Was it a used capacitor? What do you have connected to the output that audioguru thinks might cause your problem? In an earlier post you mentioned a problem with another part failing. You should check your circuit with the schematic.
MP -
Yes, a salute to full members.
I would also like to send a Welcome to all new members!
I see the site at the time of this post now has 1959 members.
MP -
Groovy, are you making a sine wave inverter using the "magic sine waves" principal? If so, there was a discussion at Electronics Forums / Circuit/General Requests / True Sine Wave Inverter on this forum. You will find links posted there as well.
MP -
Oooooh!!!! bypassing safety switches!!???!!!!
How about adding a function to the remote to do this rather than a piece of wire? You might be glad you have these safety features some day.
MP -
They both dissipate power as I stated previously. How much a regulator dissipates in dependent upon what is put into it. Yes, when there is no load, this is a different situation. But sometimes, in looking at the trade-off, a zener is more desirable to use.
....and of course, when someone posts a request for a zener, I usually give them an answer without telling them to try something else.
MP -
Siddharth,
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The transistor doesn't have to be a switching type since an LDR does not change resistance super-fast. A 2N2222 switching or 2N3904 audio will be fine.
Hate to pop anyone's bubble here, but the diagram from the data sheet is using PNP transistors. 2N2222 and 2N3904 are NPN. If you are going to change the transistor in the diagram, you should stay with PNP type. Also, PNP are better to use because a ground on the base will turn it on rather than a voltage.
PNP and NPN are not interchangeable.
MP
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audioguru, the original request was for a way to switch the power with a microprocessor. That is the first message I see in this thread.
It was you and ante who went into a discussion of triacs. You might want to go back about 7 posts and read again.
You would rather groovy has limited options?
Again, I see nothing but argument from you.
MP -
Most AT cases were common with a power supply that can handle all of the devices you have mentioned. If you find that you are adding Y connectors to add peripherals it is time to stop and think about it.
MP -
It really depends upon what the circuit is doing after it receives the regulated voltage. Try this, make a simple regulator circuit on a breadboard to power something on your workbench. Try this with and without a capacitor on the output of the regulator and watch the voltage fluctuations as the device is working and as it is needing the current.
MP -
Siddharth,
The diagram below is actually from the 78XX data sheet.
MP
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The 7805 also dissipates power. That is where the heat comes from. Any device that generates heat has power loss.
MP -
Groovy, I would also like to offer another alternative. The circuit below could be duplicated for each control pin of the microprocessor and the relay controlling the 220V line. When you send a 0 to the microprocessor pin connected to the base of the transistor, the transistor is on.
Now you have a few choices.
MP
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Thanks John, I was lost.
Timaco welcome to the community:
This circuit is dependent upon the device not sending and receiving at the same time. This is how half-duplex transmission works. I have seen quite a few manufacturers do this to save a few parts when full duplex is not needed for the circuit to operate.
Here is a link to a site that gives a very good explanation of the two communication methods with an illustration for a cable:
http://www.viddata.com/cables.htm
Hope this helps.
MP -
It seems that you are looking for this reaction between the trimpot and LDR to simulate a comparator. In that case it might work well enough for your purpose. It would not be hard to breadboard and see. I do not know the specs on the LDR. You might be able to get rid of the trim pot and make the other resistor a trim pot for adjustment. Again, this would depend upon the specs of the LDR.
Keep in mind that a LDR does not perform a switching action. It will have an analog response to different amounts of lightness and darkness. Therefore a lot will depend upon how gradual the darkness comes to the circuit. If this becomes a problem, you could add a comparator to the base of the transistor for a specific on/off threshold.
MP -
I agree. Elliott Sound Studios has quite a few schematics on the web. I see several sites with links to his when I am searching for information on google.
MP
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Yes, you are gaining ground.
What happens at 1,000? ;D
MP