Re: International standards

Thanks for the replies.

The chip is an ST TSH10 single wideband opamp.

offset

If I was laying this out and concerned about noise pickup on the offset pins, I would put a small island connected to V- under pins 1 and 8. If I could fit a trace between those pins and the adjacent ones, I would do that and connect it to V- also. That would keep the output or V+ from coupling to those pins and help keep the V- rejection at maximum.

Your sail should be a vertical cylinder, which you spin around it's vertical axis.

Oh, I wasn't sure :) I'll look at that, but I was trying to figure out if I had the problem set up right so I could derive the

What is wr? 2.pi.f ? What about P and Ar?

I'll repost in sed.

Do you mean a two wheeled balancing robot ??

Or do you mean a two motor tracked robot

or do you mean a three wheeled robot, where there is an idler wheel ?

I've just completed building a fairly long sail boat, a radio-controlled boat, which is to be powered by both batteries and solar panels, along with the help of the wind. I'd like to use separate flexible solar panels, they are extremely light in weight, to power one small DC fan and one bigger DC fan. Here are the specifications of those fans: small fan (Rated Voltage: 12VDC, Rated Power Current: 0.15 Amp, Rate Power Consumption: 1.8 W); big fan (Rated Voltage: 12VDC, Rated Power Current: 1.0 Amp, Rate Power Consumption: 12.5 W). These fans will be placed in a way that they blow air at the sails, thus propelling the boat. I would like to sail this boat for 5 hours non-stop.

My question: based on the specifications of the fans, what are the sizes for the solar panels (in terms of Rate Power Consumption) for the small fan and the big fan? Thank you.

John.

Don't be silly! How can that ever work? If you really want to use fans to propel the boat then they must exhaust freely directly rearwards.

Forget about using the small fan. It has about 1/400 HP electrical input and virtually nothing in the way of thrust. I measured less than

Then make sure your RC batteries are up to that service interval.

I don't understand the question. You already have the info in the fan specs above.

#splorf#

Beg pardon, but if you mean to do what I think you mean to do... it won't work. At best, you boat will just sit there, at worst it will actually travel backwards.

Well, for what it's worth, most easily-available solar panels seem to require somewhat in excess of 1 square foot of panel space to deliver

However, unless you're planning to sail this boat in a circular path around some sort of "racetrack", and can mount the panels and fans on the "shore" to blow air forwards at an angle onto the boat as it sails by... I suggest you re-think your idea.

The old trick of "person on boat holds fan, fan blows air on sails, sails push boat forwards" only works in cartoons. In real life, Newton's second law of motion prevents this from working.

Here there is the transfer function, w=omega.

R2*R3 - -----C*wr*P Vout R1+R3 ---- = -------------------------------------- Vin 2R1*R3 R1*R2*R3 1 + ------C*wr*P + --------(C*wr*P)^2 R1+R3 R1+R3

You can then compare this with the principal bandpass equation:

Ar --- P Vout Q ---- = ---------------- Vin 1 1 + --- P + P^2 Q

and derive the design equations from that. Well, not exactly s.e.b. :-)

wr = omega resonance = 2*pi*fr fr=resonance frequency P = complex frequency variable = j(w/wr) = j (f/fr) Ar = gain at resonance

I gave you the solution already, sorry for that. But this way you can control better your effort to derive it from the knots. You are on the right track. Start with the first knot, and sum up the currents. Then make a loop and sum up the voltages. Don't forget that the -in is a virtual gnd.

I don't think it's easy to get a 120V ballast for those.

I think your best shot is to use a computer power supply to supply 12 volts. No guarantee that it will work - the ballast may draw some large amount of current in the first several seconds of warmup, maybe 10 amps or more.

Keep in mind that a computer power supply may not work unless the 5-volt output has some load - maybe an 1156 backup light bulb.

If you want a lower cost metal halide light, then I would suggest hacking a 70 watt metal halide security light. Lowes or Home Depot may have those.

Keep in mind that metal halide lamps (bulbs) must be enclosed unless they are known to be rated for use in open fixtures. Metal halide lamp arc tubes do occaisionally explode.

- Don Klipstein ( snipped-for-privacy@misty.com, snipped-for-privacy@netaxs.com)

I'm reminded of the Good Ship Venus:

The first mate's name was Carter He really was a farter When the wind wouldn't blow and the ship wouldn't go They got Carter the farter to start 'er.

Amen to that!

Thank you. I think I will place generic largish footprints (1206) where some of these caps used to go, but not populate them until I find there is a problem. I am not looking forward to re-working SMD stuff... my eyesight will be GONE after more of this staring at electronic parts catalogs!

-- >

Right, the evaluation board I am looking at has two distinct ground planes and they are connected underneath the very center of the CPU (which has the ADC built in)

-snip-

He' s trying to put two wires through one hole. won't work.

I prepare jumper ends by forming a teensy hook (using sturdy sharp straight tweezers), then crimp that hook shut around the leg of the device I am hooking up to - as close to the board as possible (needle nosed pliers). Then solder. Then trim. If you use stranded wire you must tin the end before forming the hook. Solid wire is easier. Easy on the coffee. Good luck

I don't think that means what you think it means.

Will the sun be shining, or do you want battery power to take up the slack?

Uh, 1.8 watts and 12.5 watts...

HAHAHA!! LOL!!!

Reminds me of a Popeye cartoon, where Bluto is chasing after Popeye and Olive, who are on a ship - Popeye eats some spinach, then blows at the sails and the boat zooms off!! :-)

Seriously though, that Newton dude said that for every action, there is an equal and opposite reaction, so if the fan blows the sail, the boat will try to move forward, but the fan will also move backwards by the same amount, therefore making the boat go nowhere, or if the fan is powerful enough, rip the boat in half, then the front bit will go forward, and the back bit will go backwards - until it sinks!

Yours, Mark.

Graham W wrote:

Leemux, I had an idea about your task. If you print on each paper a small circle with conducting paint and then have on each side below the row of circles a coil that you exite at a certain frequency, the induced losses by the eddy-current of those printed conductors would be bigger with a lot of pages, so the difference between the 2 coils would be a possibility to determine the opened page. with a T-shaped core you might even shield the bottom from metallic desks. I do not know if it can be done.

andy wrote: [I wrote]

Ah, right you are, I was confusing the output he needs with the solar panel ratings. Now that I think about it, mounting "angle" and shading are going to be nightmares.

How about "as much as you can fit on the boat"? I suspect Rheilly Phoull's answer of an underwater fan is going to be your best bet...