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Re: 555 Timer Rate for Stepper- Next Counter
--- In Electronics_101@..., "Roy J. Tellason"
<rtellason@b...> wrote: On Tuesday 02 March 2004 04:02 pm, davidglaister wrote:timingHi, stepperof a 555 timer to drive a UNC5804 stepper motor driver. With the with themotor.What is this counter, a chip? Something else? I'm not familiar name you mention.wire 9On the stepper motor circuit the 555 sends a pulse to the UCN5804 that have ais pulsed.There are TTL counter chips which work the same way, and others single clock input and a direction input, which probably matchesup with what you're feeding the motor.stepper motorWould it be possible to drive the couter up/down from the would have tocircuit (I hope this makes sense). The problem is wire 8 or 9 v,be pulsed depending on the state of pin 14 (diode, transistor?)Probably easier with a small number of logic gates.I'm not sure if the wires of the counter circuit require +v or - +12vthe instructions state: Hi,pulses with respect to ground"Sounds like it's looking for a positive pulse. Thanks you for the reply. A link to the counter instructions: A link to the driver circuit: As for a counter that has a pulse input and direction input, I have found this circuit: But from what I have read on the web, it may not be suitable beacause of the "debounce" built into the circuit (or PIC). David |
Re: 555 Timer Rate for Stepper- Next Counter
Roy J. Tellason
On Tuesday 02 March 2004 04:02 pm, davidglaister wrote:
Hi,What is this counter, a chip? Something else? I'm not familiar with the name you mention. On the stepper motor circuit the 555 sends a pulse to the UCN5804There are TTL counter chips which work the same way, and others that have a single clock input and a direction input, which probably matches up with what you're feeding the motor. Would it be possible to drive the couter up/down from the stepper motorProbably easier with a small number of logic gates. I'm not sure if the wires of the counter circuit require +v or -v,Sounds like it's looking for a positive pulse. Tell me more about this counter? |
Re: Blood Pressure monitor
HSchwenk_Web.de
¿ªÔÆÌåÓýHi anmol Thanks for Your help ? Regards? Heinz ?
|
Re: 555 Timer Rate for Stepper- Next Counter
Hi,
I posted a message a week or so ago asking for advice on the timing of a 555 timer to drive a UNC5804 stepper motor driver. With the advice from this group, and some trial and error I now have the motor functioning as needed - thanks. The next thing I would like to do is connect a velleman K8035 up/down counter so I can keep track of the position of the stepper motor. On the stepper motor circuit the 555 sends a pulse to the UCN5804 that then drives the motor forwards or backwards depending on the whether pin 14 of the 5804 is fed +5v or 0v. The counter circuit counts down if wire 8 is pulsed, or up if wire 9 is pulsed. Would it be possible to drive the couter up/down from the stepper motor circuit (I hope this makes sense). The problem is wire 8 or 9 would have to be pulsed depending on the state of pin 14 (diode, transistor?) I'm not sure if the wires of the counter circuit require +v or -v, the instructions state: "counting pulses can be applied to the unit by applying +3v to +12v pulses with respect to ground" Thanks again for your help, David |
Re: design for 90-240VAC to 20VDC(3A) conversion, am i right?
--- In Electronics_101@..., "Bene Tam" <bene-tam@d...>
wrote: hi allis broken find out how to build a simple substitute. to 18VAC-48VAC, right? will be 24-68VDC, right?? some sort of switching technique out there?! other MOS switching circuit to convert that to exactly 20VDC3A output, right?? this stage is the most difficult to me, anyone can tell me more detail??
Check your current requirements and your voltage requirements. Most likly, the laptop will run on 12 and 5 VDC like home machines and possibly, 5 and 3.5 v. Since you also, PROBABLY do not need anything more than 12 VDC, don't generate 24VDC on your second stage. Using a LM7812 and LM7805 will drop the voltage to 12VDC and 5VDC regulated, but will shed a LOT of heat. A dual transformer to get 6 and 12 volts will offer a much lower voltage to start with. A simple power supply is just AC to AC via the transformers like you mentioned. Then a bridge rectifier or 4 diodes arranged in a bridge. This yields DC voltage. Add to that a capacitor that is rated for double the voltage you expect. Search this list for "Mariss" or "80,000" and find the post that referrs to how to size the capacitor. Then after cap, run the DC voltge into a voltge regulator such as a LM7812 to get 12 VDC regulated. Check the specs for amperage for the voltage regulator(s). None of this is rocket science and is a good E-101 project. Dave |
Re: Blood Pressure monitor
Anmol Sondhi
Heinz,
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Sorry couldn't mail earlier. Please check this page for more info You will find the desinger's email address there. Also you can download the zip file of the full entry from that page. hope this helps -anmol On Sun, 29 Feb 2004, HSchwenk_Web.de wrote:
Hi Anmol |
Re: tv to vga
Not necessarily. All CRT VGA monitors are analog input, and most LCD
monitors have analog inputs. However, you are correct about just getting a TV card. The original poster would have to build most of a TV plus a computer to do what he wants. A tuner with control circuits, IF strip, then split up the received signal into H and V and R, G, and B, then digitize all that in preparation to digitally rescan it to VGA frequencies. Alien Steve --- In Electronics_101@..., "ksrao_iete" <ksrao_iete@y...> wrote: you cant do it anyway since monitor contains digital elements if you |
Re: "cost reduction is king"
In a previous life, before Disney & before downsizing,
I was a video systems designer for ABC. We had a saying that "There's never enough money to do it right, but there's always enough money to fix it later". Eventually the system (control room, intercom system, truck) worked properly, but it was frustrating. Now however, with outsourcing produced projects, you'd better get it right the first time, because that's the way it's going to be. The cost is lower, but so is the usability & reliability. --- peter tremewen <Ptremewe@...> wrote: The problem with the "cost reduction is__________________________________ Do you Yahoo!? Yahoo! Search - Find what you?re looking for faster |
Re: Level shifting
--- In Electronics_101@..., "ghidera2000"
<ghidera2000@y...> wrote: --- In Electronics_101@..., "upand_at_them"The problem with using resistors on signal lines is speed. The inputs and the traces are largly capacitive so added resistance on digital signal lines slows down the rise and fall times dramatically. |
design for 90-240VAC to 20VDC(3A) conversion, am i right?
Bene Tam
¿ªÔÆÌåÓýhi all
?
I am a firmware engineer, recently my power adapter for the
laptop is broken
?
Although I am going to buy a new one out there, i would like
to find out how?to build a simple substitute.
?
There should be 3 stage, right?? AC-AC, then AC-DC, then
DC-DC
?
stage 1, use transformer, say turn ratio 5:1 to lower the
voltage to 18VAC-48VAC, right?
?
stage 2, use bridge rectifier to convert the AC to DC, the
outcome will be 24-68VDC, right??
?
but is there any combined alternative for stage 1 and 2??
seems some sort of switching technique out there?!
?
stage 3, use some sort of IC, just those from national semi.
or other MOS switching circuit to convert that to exactly 20VDC3A output,
right?? this stage is the most difficult to me, anyone can tell me more
detail??
?
Thanks much |
Re: tv to vga
ksrao_iete
you cant do it anyway since monitor contains digital elements if you
wanna do it anyway use tv card available in market. --- In Electronics_101@..., <av1a@g...> wrote: Hmm , ....this would be interesting(like channels 2-13) or just make a circut to convert NTSC video to VGA?to find a circuit for that?Service. |
Re: Converting graphics to web formats
dangermouse
Sheesh. Is THAT all?
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;o) -DM ----- Original Message -----
From: "Steve" <alienrelics@...> To: <Electronics_101@...> Sent: Monday, March 01, 2004 5:54 PM Subject: [Electronics_101] Re: Converting graphics to web formats Really busy. I'm researching everything I need to build a doppler RDF |
Re: Converting graphics to web formats
Really busy. I'm researching everything I need to build a doppler RDF
including microstrip/patch antennas and small loop antennas, gated integrators, and a load of other stuff that I need refreshers on. While getting my graphics business shifted over to doing imprinting (tshirts, mugs, etc). Plus my wife and one of the schools here wants me to come in and do some science classes. And I am attempting to set up a video capture/editing computer in my spare time with nearly zero money. And learning to program PICs for use in props and test equipment. And that's a small fraction of the pies I have my fingers in. Look for links on microstriplines, small antennas, and anything else related to my project. Alien Steve --- In Electronics_101@..., "dangermouse" <dangermouse1956@g...> wrote: Good man. You've been busy lately, huh? |
Re: what component to use to build a bridge rectifier??
¿ªÔÆÌåÓý??? ??? The problem
with the "cost reduction is king" approach I have always found, is that when it
eventually does fail,? you are the one who wears the blame for the fault.
Clients don't wont to know that it broke down cause they didn't want to pay a
few extra dollars for surge protection. Whenever a client comes up to me and
says "I can get it cheaper down at blah, Blah" I simply tell them that I sell
middle of the range equipment and that the slight extra expense is worth it when
you consider the cost of? break down. I consider the few clients I loose
because of this are just not worth the trouble they will cause
latter......? When I am asked to do so, I have a reputation for producing
reasonable quality reliable equipment.....?? Most people, especially
those who I have previously dealt with, ?are willing to pay just a little
bit more for that I have found......
?
??? ???
??? ??? The Sinister Dragon
?
Of COURSE surge protection, and a gazillion other things besides, are in |
Re: what component to use to build a bridge rectifier??
dangermouse
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----- Original Message -----
From: "Roy J. Tellason" <rtellason@...> To: <Electronics_101@...> Sent: Monday, March 01, 2004 3:41 PM Subject: Re: [Electronics_101] Re: what component to use to build a bridge rectifier?? Though if the industrial environment in question is *that* nasty thenmaybe surge protection is in order, before it gets to the rectifiers...I had to re-compose myself for a few minutes after reading that comment. Not because you aren't right, but because you are, and other things... Of COURSE surge protection, and a gazillion other things besides, are in order. But in most industrial environments, cost reduction is king, and the bean counters in the front office get to say which costs get "reducted" and which don't. In other words, that's why we sub a few .10 1N4007s into circuits, and have quit trying (except for a few notable cases) to sell large-scale protection to most industrial clients. They just aren't interested. -DM |
Re: what component to use to build a bridge rectifier??
Roy J. Tellason
On Monday 01 March 2004 02:41 pm, dangermouse wrote:
Perhaps that's true for consumer-type work, but in industrial environments,Oh sure, if I'm gonna buy some I'll probably just go ahead and get the 1000V parts, the price difference just isn't worth it... Though if the industrial environment in question is *that* nasty then maybe surge protection is in order, before it gets to the rectifiers... |
Re: what component to use to build a bridge rectifier??
dangermouse
You're right, it's 1N4007. When Peter said 4008, I just parroted him rather
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than check it for myself. See? It's someone else's fault. I never make misteaks myself... -DM ----- Original Message -----
From: "Roy J. Tellason" <rtellason@...> To: <Electronics_101@...> Sent: Monday, March 01, 2004 2:39 PM Subject: Re: [Electronics_101] what component to use to build a bridge rectifier?? On Monday 01 March 2004 12:21 pm, dangermouse wrote:expectI'm not sure if anyone has mentioned this yet, so sorry if I'm just forthe diode to see. If you expect the highest voltage to be 120VAC RMS, (sqrt(2)),example, the peak voltage will be about 170V, or RMS voltage x theand your diodes must be sized to handle that.Good point, and it's not just the peak AC voltage, but the peak capacitor that's typically connected to the other side, which under no orI'd feel more comfortable going higher.(they'reOf course, if you follow Peter's advice, which I most certainly do yourcheap and much less likely to fail from some unanticipated transient), 1N4008 diode won't much care whether you give it 120V or 170V, as it's1N4008? My chart only goes up to 1N4007, which is shown as a 1000V part. |
Re: what component to use to build a bridge rectifier??
dangermouse
Perhaps that's true for consumer-type work, but in industrial environments,
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which are notoriously nasty (chemically, thermally and electrically) that 1000V PIV is wonderful for preventing failures due to the guy down the hall starting and stopping his welder and other such stuff. -DM ----- Original Message -----
From: "Roy J. Tellason" <rtellason@...> To: <Electronics_101@...> Sent: Monday, March 01, 2004 2:35 PM Subject: Re: [Electronics_101] Re: what component to use to build a bridge rectifier?? On Monday 01 March 2004 12:19 pm, Phil wrote:what--- In Electronics_101@..., "Roy J. Tellason" we're doing with electronics these days, the higher voltages were onlyrating of 1000V and 2.5A, I used to buy bags of 25 of them, though I don'tthink I ever quite finished using the last bag completely.care what the reverse voltage is as it's never going to see all that much. |
Re: Looking for a mentor
Roy J. Tellason
On Monday 01 March 2004 01:44 pm, mattnyc_ wrote:
Hello,Heh. I used to live in that county, but I ain't moving back there to help you out! :-) What is it that you're trying to do? |
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