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  1. windoze killa

    Wattage lowering

    The 72W is probably 72W PMOP which basically translates to the O/P power just prior to melting. There is really only one power measurement and that is RMS. It would be handy if you can find out what the RMS power of this amp is. Would be much easier to say if the speakers will handle it. If the...
  2. windoze killa

    Voltage level shifting

    Well I actually need 5 OP amps as there are 5 currents I need to monitor so I can get away with 2 chips. The good news is that I have got it working with LM324s. Bad news is we are back to 5V supply and rail to rail amps. Hopefully I will have this sorted by the end of the week. Thanks for...
  3. windoze killa

    Musical fountain

    Correct. That means the fountain will spurt water differently for every song. Would be a bit boring if it didn't.
  4. windoze killa

    Musical fountain

    If you were to have specific filters for different ranges of frequency of the music you can have the O/Ps of the filters control different jets of water. Bit like the old musicolor light displays.
  5. windoze killa

    Voltage level shifting

    Good idea. Didn't think of that. Unfortunately I don't think we will have the real estate on the PCB. Pretty much why we are using op amps as we can get 4 in one package. And also the softies won't need to write anymore code.
  6. windoze killa

    Voltage level shifting

    Guess what. In the process of building up my circuit I have been informed (after 3 weeks of toil) that I can have a 10V rail and have to use an LM324. Not bad seeing I was supposed to have this design finished last week. Oh well back to the drawing board. While i am trying to work this out I...
  7. windoze killa

    4PDT to SPDT trick

    Try putting a voltage divider with a pot on the other input to the comparator. Adjust the pot to cancel the small voltage you are seeing on the other input. You could even go a little further so you need a high voltage to switch the comparator.
  8. windoze killa

    Timed resistor

    You can make a 555 do almost anything. But what you require is a pulse, one that can be varied from 0s to 180s. You can do this using a pot and capacitors or you could do it with fixed resistors and capacitors and use a switch to select fixed delays.
  9. windoze killa

    Timed resistor

    Sounds like a pretty simple task. All you need is a 555 timer. There are plenty of circuits on the net that should do the job for you.
  10. windoze killa

    3phase control circuit

    I can't think of any specific parts of the top of my head but there are heaps of ICs out there for driving 3 phase model engines. In particular brushless motors for model aircraft.
  11. windoze killa

    Terminating a cable with a metallic braid

    The metalic braid you are refering to is the shield of the cable and is generally connected to earth or ground. If you are talking about a cable designed for audio then you can comb the strands out and twist them together. This and the centre conductor form an un-balanced cable. You terminate it...
  12. windoze killa

    Voltage level shifting

    You are partly right. This voltage will be fed into a micro but the I/P has to be 0V to 5V. The code in the micro is being used in many places and all the other inputs are 0V to 5V so we can't change the code just for this one. They are to be interchangable between each other. I will give you a...
  13. windoze killa

    12V to 5V

    A good rule of thumb concerning power supply caps is 10 uF per amp. Seeing as you require 6A then 60uF would be a good choice. As 60uF isn't a standard value the 47uf or 68uF would do the job. Capacitance is really only critical in switch mode PSUs. If you decide to go with a SMPS then I would...
  14. windoze killa

    Question about amplifier

    Certainly. But can we have a bit more info. Type of amp? Audio? RF? Type of active device?
  15. windoze killa

    Voltage level shifting

  16. windoze killa

    14 3v LED's powered by 12-15vdc

    You probably don't want to connect them in series. In this configuration if one fails none of them wil remain lit. This will also mean you will have to check each one to find the dead one. If you have them in parallel then only the one that dies will be unlit. Although these LEDs have a built in...
  17. windoze killa

    help needed

    Something I always suggested to my students when they asked for a project was test equipemnt. Build yourself a capacitance meter or function generator or frequency counter. They are always usefull.
  18. windoze killa

    Voltage level shifting

    Thanks Pebe but I am not denying that it may work. It just doesn't seem to work in Altium designer simulation. When you pay $10K for a program you expect it to work. I am still obviously missing something. I have also put your other simpler single amp into Altium as well and it doesn't seem to...
  19. windoze killa

    Audio amplifier

    Pretty much yes. So long as you observe the power requirements of the earphone.
  20. windoze killa

    Voltage level shifting

    Well we need a load resistor. This shall be driving into an analog I/P of an AVR. With a load of 100K I get an steady O/P of 1.5V. 1M gives an O/P of 0V No load gives an O/P of 5V This doesn't make sense. I am obviously missing something. I shall pull out that dusty 20yo book and read some more.
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