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# Fowkc

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1. ## RC Circuit (How?)

Clarify what's happening here... in the first diagram, pin 4 is normally closed. In the second, it's normally open... You'll have to experiment to see what voltage your relay turns off at. I'm not sure how your second circuit is meant to work, but I can see the principle (using a capacitor to keep the relay on). Assume the capacitor starts charged at 12V, work out how the voltage on the capacitor changes with time, then use that equation to get the capacitance you need for a 1s pulse.
2. ## Reading Pulse signal from a flow meter

There are a number of PCI and USB based dataloggers/oscilloscopes avaliable for the PC. Any number of these would work, but they're quite expensive and perhaps a bit over-the-top for pulse counting. Google "PC datalogger" or something like it.
3. ## Lets make our printer wireless !

I have considered this in the past. Using IR is interesting, but probably quite complicated. To get full functionality, you'll need to buffer whatever data the computer sends, send it one bit at a time via IR, plus any status bits. You'll then need to re-compile those bits into a parallel stream and send it to the printer, at the same time dealing with any stauts bits the printer can output. I'd say it's more than possible, but the IR bit is probably quite simple compared to getting the data conversions done.
4. ## Protecting the motor

The device you use will be put in series with the motor. When the motor is stopped/stalled, the current through it will increase. So your polyswitch or current limiting circuitry will trip the circuit if the currnet rises too high.
5. ## free energy motor

Anyone else reminded of "all your base are belong to us?" Sarcasm aside, I have not seen one overunity site that actually describes HOW the thing is meant to work. There are very vague allusions to bits of particle theory, mostly virtual particles that are somehow tapped by this carefully timed motor. Most of the sites do not have a single equation in their desciption that might shed some light on the mechanisms behind the operation of overunity devices. However, most sites DO say something like "overunity devices have been around for years!" Funny then, that not one single commercial product has been sold. Lots of patents issued, but no products sold. Could it be that on close inspection, they don't actually work? I know I'd like to buy a device that meant would never have to pay energy bills ever again...
6. ## free energy motor

So, if we accept the rather dubious premise of "phi-flux", how does the circuit harness this energy? You mention timing circuits, but it's all a bit vague. For instance, you say there is "no Lenz law". Normally all the components in the circuit you posted obey all Maxwells equations. What is special about the configuration here?
7. ## Numeric counter displayed in 7-segment LED

Those are the ICs you need, so it's just a matter of wiring them up correctly: http://www.aaroncake.net/circuits/counter.htm Make sure your seven segment display is a common anode type if you're using this circuit. If not, either find a common anode type, or swap the 7447 for a 4511
8. ## Help! Connecting power supply to small load/solenoid

A solenoid is not really a "short circuit" in the normal sense of the word. If you drew out the wires in a solenoid or inductor, the behaviour would be of a normal piece of wire. The coiling up of the wires means that the coil creates a magnetic field inside it. This magnetic field in turn sets up a voltage across the solenoid which will oppose the applied voltage. The measurement of the resistance of a solenoid (as far as I know), is not a very good indicator of the current it will draw, as the behavior is dependant on that current. Think about a transformer winding: low resistance, but the behaviour when a voltage is applied is very different from a resistor of the same value.
9. ## free energy motor

So what is the motor powered by? What are the physical principles behind the motor turning? I think we're all a bit confused.
10. ## PCB Etching Tank - Do it yourself

I already etch lots of one off boards, current process is printing onto tracing paper, UV exposure, develop and etch in a plastic tray. This would be fine if I didn't share a house with four other guys. If it could go a bit quicker and be a bit more "self-contained", I'd get in the way less. Thanks for all the help, sorry I was a bit insistent. I was sure it would work, I just like to understand why.
11. ## PCB Etching Tank - Do it yourself

I haven't actually bought anything yet, I'm collecting information. I'll only be etching one-off boards, so I won't have a lot of etchant to heat. I'm still not sure about this, you say: Well "top-of-the-scale" for the aquarium heaters I've seen is about 32C. Presumably you get your etchant hotter than that, so how do you do it? Do your heaters go higher than that temperature, or is it a result of heating much less liquid that they were actually designed to heat?
12. ## PCB Etching Tank - Do it yourself

OK, what sort of wattage heater should I be looking at then? It seems to be the case that a more powerful heater is meant to heat a larger volume of water (i.e. larger fish tank) to the same temperature (about 32C), rather than actually increase the temperature any further and kill your fish. I can see how a more powerful heater would pump out more heat initially and then pretty quickly turn itself off as the etchant reached temperature, but it would still try and keep the temperature at about 32C. Obviously I'm mistaken, since lots of people have done it and it works, but I'd like to understand why...
13. ## NEED HELP IN A BAD WAY.... LED PROJECT

Hmmm... can't remember how I got round that... perhaps it wasn't an issue, not sure - it was a good few years ago! But there must be a way around that problem. The last 4017 output could be used to turn on a PNP transistor to switch the SCR power on. When that output goes high, the transistors turn off and the SCRs reset. Again, it's not elegant (you only get 9 outputs), but it probably works.
14. ## PCB Etching Tank - Do it yourself

I keep meaning to build myself an etch tank, but one thing eludes me: People use aquarium heaters to heat the etchant, but all the aquarium heaters I've seen have a built-in thermostat that keeps the water at a maximum of about 32C, about 10-15 degrees too cool. How do you get around this, or is there something that I'm missing?
15. ## NEED HELP IN A BAD WAY.... LED PROJECT

Sounds similar to a project I did for GCSE. I had the 555 clock a 4017 decade counter. Each output was connected to a thyristor that turned an LED on. Thus after 10 pulses, all the LEDs were on. It's not the ideal solution, because it requires 10 discrete thyristors, but it worked.
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