Re: International standards (2023 Update)

A solenoid doesn't deteriorate, electrically. It will wear mechanically, however, and gunk from the air could gum it up. But ampere-turns are ampere-turns, I'd think.

Are you really losing downforce, or do you just have dull blades?

Good Luck! Rich

Do you mean that you have components just lying there loose? Then, although you don't want to hear it, you can essentially do anything you want to. But your question is kind of vague. And I don't know if you have the background to start cutting holes in sheet metal, if you need someone to say "use an[sic] sonic screw driver to cut....". Which doesn't make any sense anyway, by the way.

Go shopping around. OC? Geez - go to the malls and look for educational toy stores with construction kits. Go to industrial liquidators and check out relay racks. Go lurking in the hobby/recreational build-stuff newsgroups.

But saying, "I want to put some stuff in a cabinet, but I don't know what I want to make it out of or what I want it to look like, and by the way, I've never had a tool in my hand, so I need detailed instructions down to how to put a screwdriver blade into the slot" probably isn't going to yield much in the way of useful information.

Good Luck! Rich

Oh, yes - sorry for condescending there. :-) The Newark/Mouser/Digi-key et al catalogs probably have a wealth of hardware. For a flat piece of sheet metal, how about a case side from a "retired" computer? If you have access to a brake, bending some little upside-down-U-shaped brackets might be cool. When I was a kid, we got an Erector Set for Xmas one year. I don't know if you can still get such a thing, but you could build little superstructures and trestles and stuff, if you want. Erector Sets are _way_ cool. :-)

Have fun! Rich

Hello,

Does anyone know the 5A COnstant Volatge/Constant Current Regulator from the LM117/LM317A/LM317 regulator, it's on page 16 and is downloadable from

I am curious as to the reason from R7=220. What will happen if we put R7=0R ?

I have, and it is not the blades...thanks anyway

Disclaimer: I am not a student, but a home hobbyist trying to work out a problem.

Here's the situation. I have a 1Mhz osc which I want to switch on-off. The issue is that I don't want the on-time of the clock to change depending on when the switch is thrown. Im looking not for answers, but for pointers or suggestions on how I should work this problem. The angle I have tried so-far is to use a edge triggered flip-flop to catch the output of the input osc ANDed with the switch input. The idea here is that if I catch the edge, and it's active, then I can send this through a one-shot, or somthing else to keep the width of the pulse the same size. However, this seems kind of complicated, and may require a debounce on the switch as well... Is there some simpler approach im missing? Thanks, Ron (rwatkins at dssolutions dot com)

I have a question which was posed to me yesterday. "I" am not familiar with LCD Computer Monitors from Lap tops past the point of looking at one as I am now to type this. I've never taken one off, or even peered into the inside of a laptop or seen any schematics for an LCD display to have been able to even come close to answering this question.

The question was.....

Given there are many used laptops out there with colored monitors, is there a way they can be removed from the laptop and voltages applied - including any reference voltages - to be used to hook up to a DVD player or some other unit needing a video display????

I will forward all replies to my friend, and I thank you in advance - as I too will learn something here. My field is electronics, but we can't know everything - can we? I'd love to meet the person who claims to.

L.

Greetings, I'm going to build the battery desulfator circuit described here:

. Looking at the schematic it appears that C1 and C2 are electrolytic capacitors. Can the other capacitors be disc ceramics? Or is there a better choice? Finally, what kind of device is Q1? Thank You, Eric R Snow

How do I calculate the peak current flow when charging a capacitor?

To be specific I want to connect a capacitor (among other things) to the output of a 74HC595. There will be a diode between the IC and the cap. What is the maximum size capacitor that I can use without blowing up the chip?

No limit; you won't blow up the chip doing this.

John

The Jameco catalog doesn't have any inductors that are 1000 micro-henrys. Only less. Can these be connected in parallel or series to increase the inductance? Or is it easy to wind my own accurately? How can the inductance be measured? I have a Tek 465B 'scope but I'm still learning how to use it and don't know if it can be used to measure inductance. Do I need a ferrite core? I have a machine shop so making the mechanical parts to wind coils is easy for me. Thank You, Eric R Snow

Hello,

Is the following psu any good

The voltage reference is taken from the output, wouldn't it have made more sense to had some sort of zener diode reference, I mean, any input ripple is going to be present in the output, and worse still it will be amplified by Q1 so the output ripple will be even worse than the input ripple. This circuit is bad, isn't it?

HArd to say without more osc circuit details but I'm quessing this osc is made with inverters (?) Why not use a SPDT or dpdt switch with one side to turn on the OSC supply and the other (when off) to ground out the timing cap to return it's initial condition to 0V?

--
Best Regards,
Mike

I'm trying to fade some lights off slowly using a mosfet (see separate posting Fading Lights from 22 July) driven from a PIC and 74HC595 shift registers. I've encountered some strange results.

I actually have 7 identical mosfets with 7 strings of lights attached, each string of lights drawing a different amount of current. Each

74HC595 output runs via a diode to one mosfet gate. The lights get turned on at different times then I want them all to fade off together.

To create the fade I added a small cap to each mosfet gate (0.001uF). The first thing I noticed was that the higher the load current the faster the lights turned off. I therefore had to vary the size of the caps to get a uniform fade time across the 7 strings.

The smallest string of lights however was turning off too slowly even using a 0.0001uF cap. I therefore removed the cap completely. To my surprise that INCREASED the turn off delay - so much so that the mosfet overheated badly. Why the increase in turn off time? Would it be due to the leakage through the external cap actually draining off the mosfet gate cap once the external cap discharges?

Next problem. Increasing the size of the gate caps does not increase the period of the fade. It simply keeps the lights on at almost full brightness for longer, then they die very rapidly. The actual fade time remains constant at about 0.7 seconds no matter how big the caps. (I need about 1.5 seconds). I am therefore thinking of reverting to transistors instead to try to get a slower fade.

(I am driving it from an 8-pin PIC (Picaxe) but I can't do PWM for various reasons.)

Thanks..... I'll pass it on. I'm not much of a TV enthusiast to watch my TV in the living room, let alone carry one in a car or portable. I use my TV to put me to sleep! Anyway, as I said, I was asking for a friend who posed the question to me yesterday after he was looking at some LCD monitors for DVD play back - in Circuit City. He doesn't have access to news groups to ask, so he knowing I did, thought I could put a feeler out to anyone who may be able to give a reply. He has limited electronics experience and may even want to play with the ideas as presented. All I can say to him is GOOD LUCK!

Thanks again!

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Thanks, I'll forward this on.... I appreciate the response.

L.

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Thanks John. And I really meany C1 and C4 but somehow my finger typed C2. Hmmm.... Can you tell me if this device from Fairchild will work instead of the IR part?

. Mouser doesn't carry the IR part and I don't know enough to decide which of 33 Fairchild parts will work. Also, Do you know of an on-line source that expalins how to wind your own inductors accurately and for a novice? I've looked but haven't had any luck. Cheers, Eric

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You would have to wire up every blessed apple to stop "dem critters" from getting them. Learn to share, or learn to like squirrel meat. Tom

At about the time of 08/01/2004 11:37, Gary Reichlinger stated the following:

Sorry about that, no insult was implied or intended. It's one of those automated taglines I came up with a long time ago. Just haven't gotten around to changing it and completely forgot about it. It's changed now.

The other reason that I'm going for full isolation is that the microcontroller and motor are powered from completely separate supplies.

--
Daniel Rudy

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