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  1. Merlin3189

    Type of filter

    Beats me. A few more connections might help a bit. There is a Wikipedia entry on filter topology you could try. I wonder if it's just a volume control? Or even a balance control. Depends which wires go where.
  2. Merlin3189

    RF Generator with 1600Vdc output 20KW

    Should anybody really worry? What's he gonna plug it into? If can put out 20kW and consume 53kW (just going by his link), won't the fuses fry almost as fast as he does? (And the connecting cables as well!)
  3. Merlin3189

    Multimeter?

    Can I just chip in my own sore point about multimeters? That is resistance or current drain. When I was young, this was the main specification for a meter, but these days it doesn't get a mention in most meter specs. Even Fluke don't quote it in their sales literature and you have to look in...
  4. Merlin3189

    stepping down 300v ac

    So what's wrong with a simple resistive potential divider? If your meter (or sensor?) wants a maximum of 5V when the transformer is giving 300V, then add a resistor in series, which is equal to 59x the meter's (or sensor's) input resistance. If the input resistance is already large, you can...
  5. Merlin3189

    stepping down 300v ac

    Oh! Sorry I've just realised that you wanted the 5V as AC, so that nullifies my whole idea. In that case you may as well stick with a dropper resistor or capacitor. But still use the 300V tap for the input. There's no point in stepping the Voltage up from 220 to 300 when you really want it...
  6. Merlin3189

    stepping down 300v ac

    So, you have 220V supply, you use the auto transformer to step it up to 300V, then you ask, how to use a 220V transformer with this 300V supply! Why not simply use the 220V transformer with the 220V supply? That would give you 12V rather than 5V, but that would probably drive a 5V...
  7. Merlin3189

    horizontal polarization of a satellite signal

    Since the geostationary sat is on the equator and the polarisation is in the equatorial plane, I'd have thought that at any point in the radio field, the polarisation would be parallel to the equatorial plane and all observers would see it locally as polarised parallel to their local plane...
  8. Merlin3189

    Realization of an audio amplifier ..

    If you have two speakers of "4 Ohm/8 Watt each", what is the maximum power output? What is the efficiency of the power amplifier stage you plan to use? So what power do you need to be able to supply? Alternatively, just design the amplifier, then calculate its power needs and then specify...
  9. Merlin3189

    Rayleigh channel

    To be honest I'd never heard of this, but maybe something like this might help? http://www.mathworks.co.uk/help/comm/ref/rayleighchan.html
  10. Merlin3189

    Is this true or false

    http://en.wikipedia.org/wiki/Insolation Apologies for my frivolous reply. I thought most people would cotton on. As for my amount, "100W/sqmetre or more", I had in mind a figure for the UK of around 350W/sqm which I had seen quoted, but as it was a cold, miserable, cloudy day here (so I was...
  11. Merlin3189

    The calculus of FM super heterodyne receiver

    Wow! A very impressive bit of research. Having looked at the WikiP article I'm not surprised you're a bit confused. I'm supposed to understand this stuff (or at least I was once) and I struggled with that article. I don't think I can deal with all your questions - you cover a lot of ground...
  12. Merlin3189

    stepping down 300v ac

    So what is the input to the transformer? And if 300V is the maximum output, is there a lower one?
  13. Merlin3189

    stepping down 300v ac

    Where does the 300V AC come from?
  14. Merlin3189

    Multiplexing project

    I've read the comments here and elsewhere ( http://www.eeweb.com/electronics-forum/multiplexing-project/ ) and see nothing very interesting about the multiplexing issues. But I must say, these ferrofluid valves sound very interesting, whatever the application. So it would be nice to know what...
  15. Merlin3189

    diodes in parallel

    Just out of interest, why do you need to put milliOhm resistors in series? For current balancing, I'd think you'd need more. To worry about inductance (this small) you must be using quite a high frequency and presumably these are power diodes rather than signal diodes? Can you not just use a...
  16. Merlin3189

    Switching possibilities

    Any chance of seeing the circuit?
  17. Merlin3189

    AM transmitter construction

    Can I add my weight to Davenn: this is not the way to go, if you are a beginner, even with good electronics experience. I know a professional electronics engineer who 10 years after getting his licence decided to design his own transceiver. He found it difficult. There's a lot of knowledge...
  18. Merlin3189

    Is this true or false

    If we use radio waves from space, no one could complain (except, perhaps the little green men!) The cosmic background radiation is probably too weak to help much, but here on earth we receive signals in the 400- 800 TeraHertz band which have powers around 100 W/sq metre or more. A little...
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