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bobleny
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Posts posted by bobleny
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Now, we use calculators on a day to day basis, but how do they work? Most of us know that a basic calculator has a basic IC to perform the algorithms. I had a few questions I was hoping you could answer about this.
Everything in electronics deals with logic. If a condition is true, perform this action, if this then that. I know that 2+2 is equal to 4. However, a calculator doesn't "know" this. Its function is to figure it out. I'm just wondering how it does this. I can't figure out why 2+2=4. I have no idea why 2+2=4, I just know it does, so I've been told... My 50 cent calculator can figure it out though.... So here where my main questions.
What is the logic of these circuits?
How does it differentiate between a 0, 1, 9, or an 3?
What is the logic circuit used to preform the mathematical computation of 2+2?
I would really like someone to break it down step by step and perhaps provide a basic diagram of the logic used. I don't need to know the components to build a calculator, I just want to see the gates a calculator would use to perform 2+2.
Edit: I think the diagram I am thinking of is called a block diagram.... -
Ha! Theres a billion and ten ways to do programs...... lol
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The datasheet for the LM555 has a graph to select parts for a certain frequency. Changing the resistance of only one of the two frequency-determining resistors affects the duty-cycle of the output.
Well, I wanted a formula. I made 5 different programs on my calculator so that I can type in values and it will give me an answer. They work so well! It made getting the correct components for my 555 so fast and easy!
Prog1 - CAP:
Give it values:
Frequency: 1.3 Hz
Resistor 1: 1000 Ohms
Resistor 2: 10000 Ohms
It tells me I need a capacitor of ~52.74 uF to make all the values true!
Prog2 - DUTY:
Give it values:
Resistor 1: 1000 Ohms
Resistor 2: 10000 Ohms
It tells me that I have a .09, or 9% duty cycle. I am dealing with a duty cycle of less than 50%...
Prog3 - FREQ:
Give it values:
Capacitor: 52.74 uF
Resistor 1: 1000 Ohms
Resistor 2: 10000 Ohms
It tells me my frequency is ~1.3 Hz.
Prog4 - R2:
Give it values:
Capacitor: 52.74 uF
Frequency: 1.3 Hz
Resistor 1: 1000 Ohms
It tells me that resistor 2 need to be ~10001.44 Ohms.
Prog5 - REVEDUTY
Give it values:
Duty Cycle: .09
Resistor 1: 1000 Ohms
Frequency: 1.3 Hz
It tells me that in order to obtain a 9% Duty cycle, resistor 2 needs to be ~10111.11 ohms and the capacitor needs to be ~52.19 uF.
It is really nice to be able to tell it a few things and it give me an answer rather than trying to figure out the answer your self. Now I need to put all 5 programs into one really nice program and post it online!
I like making programs for my calculator! I've made a few games and even created a program for Ohms law! You type in what you know and it tells you what you don't know. Like, say my current is 10A and my resistance is 60 Ohms, it tells you voltage. It said, "E=I*R:600". It comes in handy on those long days when you don't feel like doing any math!
I then designed a program for the resistor color code. I know it by heart but what the hey. I never got around to finishing it. It gives you a menu of ten colors where you pick the first color. Then another menu of ten to pick the 2nd color, a third for the 3rd color, then a 4th menu to choose the last color, gold or silver. It then tells you the resistance of the resistor and the +- tolerance of it as well.... It's really neat!
NOW YOU KNOW!!! -
Thanks! That works... I had F/C instead of F*C some how.... lol
Thanks! -
I have this formula:
How do I work this formula around to equal R2?
I tried a bunch of times but I don't know how to do it I guess...
Thanks! -
Thanks! I set it up and it clicks my mouse perfectly! thanks!
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Will the resistor at the base effect the circuit any?
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Well, I don't know what you just said.. ??? :-\
However, when the mouse button is suppressed, one of the pins of the IC is connected directly to ground. What I am trying to do is create a signal (done, with your help...) and use it to connect that pin of the chip (not "ship" :-[) to ground.
So, because I don't know what you just said, I don't know if it is needed?
Oh, and what value resistor do I need at the base of my transistor, if any? -
Well, how much current do you think is passed when a mouse clicks? I will check...
Ok, This meter reads .1mA...
I don't know if it is right. I don't know how to test a meter to see if the amp setting is correct. My multi meter is correct, but sadly, it is at school. :(
Just real quick how do I make sure my meter is reading amps accurately?
Does .1mA sound right to you? -
The "ship"!? What is a "ship"?
I have no idea what transistor I need to do this. I only have a couple of them... I know I need a NPN, but other than that, I know not.
Here's my circuit:
Problem with this circuit, with the 5v power supply out of my PS2 mouse controller in my computer, I don't have enough juice at the end to close the relay. I'm hoping that the the transistor wont need so much juice to close... Not that it really closes.
What would you suggest for a transistor in this case?
I have two transistors...
2N3904
MPSA20
I can get others from radio shack too... -
Point taken, I forgot about the resistor in series with the LED...
By a positive signal that controls a negative signal, I mean, I want to take the logic high signal from a ship, and use that to connect the ground, or the negative terminal on my battery, to a device.
I really cant explain it well....
But if you guys say the circuit is right, with the exception of the led, which wont actually be their, then it should do what I want it to do.
Thanks! -
Hi, I drew this circuit in hopes it will replace my reed relay, but I do believe this is wrong... The idea, is to make a positive signal control a negative signal.
Thanks! -
My personal favorite, make it hell to sign up.... You wouldn't do it for long... few months...
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Hmmm... Glad you brought this up. I can't believe I didn't show you... I could have sworn I did! I know I did in another topic. I wonder what you guys think of this. I drew this up some time in october. I think It will display a seemingly random light pattern.
I'm considering a micro controller instead..... -
That's cool!
Thanks for the link.... -
I have a masters degree in mechanical engineering, associates degree in electrical engineering and a bachelors degree in computer science (not computer engineering). I just got my A++ certs!
I'm currently going to the University of Cincinnati (UC) for my masters in electrical engineering. They have this great CO-OP program where I get on the job experience, this is paying for most of my fees!! Didn't coast as much as I thought either. I was thinking $30,000 a year or something crazy like that. I almost didn't look at as an option, glad I did though...
I went to Columbus Tech for my masters in mechanical engineering. I worked at Sandee laboratorys in new mexico for a few years designing designing a bunch of crap for the government. I think I like the Tech school better than UC as I didn't have to take english and history... Bluack!. :-X
I got my bachelors in computer science at Columbus Tech as well... It was something I kinda picked up while I was there and did some classes for it. That was fun... :D That's how I got into electronics, actually. I liked working with computers so much I started to dabble in electronics as a side hobby. repairing Computer motherboards when some idiot screwed them up because they thought they could fix it. And here I am today...
My whole life laid out for all to see and all at the age of 18! :P -
Well, I have linux and I could have sworn there was a binary package available. If not, I might compile a binary package. If I ever get the time!
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LOL!! :D Your sarcasm is hysterical! WOW... lol
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Sorry Bob,
I thought you were the guy who tried to blow up his 555 and LEDs.
I gathered... lol
Ashkwil, might I ask what you need this circuit for? We might be able to suggest a duty cycle and frequency... I know it is for your RC but what part? Does it need to oscillate a certain way to control something inside, or is it a light to tell you the car is on? The voltage source is always nice to know as well... -
Hi Bob,
You still didn't say what is your supply voltage.
Uhh...? I never said anything about a supply voltage...That is if you didn't burn it out when you tested it without current-limiting resistors.
umm... I'm not sure I have ever burnt out a 555! I've tried, sadly failed!It tries to provide more than 200mA into the LEDs that have a max rating of only 30mA.
I have known this for quite some time now...Did you try a better duty cycle by swapping the positions of the resistors?
I didn't have to, I used a circuit that I built a while ago with a 50% duty cycle at about 1Hz...Did you slow it down?
No, it was already at 1hz and I was just wondering if they would actually oscillate back and forth...
LOL! WOW! I think you might have gotten a tad bit confused here...
I'm not the one with the 555 timer difficulties here... I feel that I am quite proficient with the 555!
And, BTW, I have answered my question with further analis of the circuit. Thanks anyways....
lol, still confused? -
I finally did it! YAY! it turned out super crapy! I don't know what I did wrong... I think in part the photo paper I used sucked... My lines whern't thick enough either I don't think. I only made them 3px wide.
I had questions...
The paper stuck to the toner, was it the paper, did I iron to long/short, maybe both?
How many pixels should I make the lines?
How many pixels should the holes be to be able to drill a 1/16" hole? -
I have downloaded this program and from what I can tell is pretty good. It allows for multi layer PCBs and other functions. As soon a I figure out how to run the dang program ( lol ), I'll tell you how I like it. So far, I don't like it, I really can't figure out how to run it!!
http://pcb.sourceforge.net/ -
Wow, 95% duty cycle....
lol... BTW, it's 7.2Hz ;D And considering the duty cycle, the top LED should be on longer than 19 times....
Actually, I am surprised the bottom LED works at all.... I didn't know the 555 produced a negative signal when its output was low. I thought it was 0 volts.... Learn something new everyday! :D -
I probably won't need a lot....
Thanks!
Headphone jack to antenna jack?
in Electronic Projects Design/Ideas
Posted
Hey, can someone tell me how to take the signal from a CD player's headphone jack and plug it into the antenna jack of my car radio?
I'm not looking for a FM transmitter or anything like that. I want to unplug the car antenna, and plug the CD player into it.
Is the headphone jack digital or analog?
Is the antenna jack digital or analog?
That's all I need to know right now. I hope they are both analog...
Thanks for you help!