Search results

  1. I

    Using multiple monitors - Help?

    hi stuee i am sorry still trying to fing the damn thing give me some time i will find it here somewhere.. ian
  2. I

    Design of PC Speaker

    yes you are right sorry for the wrong info but i did state that smartsarah2003 should expriment with different values
  3. I

    How Microwave Oven Work?

    basically it  vibrates the molecules at microwave freqency which in turn generates heat
  4. I

    Design of PC Speaker

    if you take one wire from the normal speaker and connect it to one side of a 1uF electrolyic cap then take the other side of the cap and connect it to the tweeter then take the remainig lead of the tweeter to the remaing lead of the normal speaker experiment with different values and you will...
  5. I

    different btw A/D and digital PWM

    a/d = analogue to digital therefore to convert analogue to digital  one would sample the analogue signal a given number of times each time a sample is taken a digital byte is recorded represented by ones and zero's depending on the resolution this word could be 8 bits or 14 bits etc long this...
  6. I

    function of these two units~need it urgently

    a down counter  take a predetrmined number and subtracts it  one by one over a predertermined time. a zero detector usually detects the balance in wheatstone bridges a pulse generator will generate a pulse of predetermined width and amplitude
  7. I

    Design of PC Speaker

    usually the  volume control is in the pre-amp section varying the gain of the first amplifier. the most simplest way to get rid of the loe frequency's is to put a cap of 1uF in series with the tweeter.  plse note this is the meanest and simplest way.
  8. I

    ir operated door

    is the motor dc or ac
  9. I

    Special IR Circuit

    the circuit here with is realatively simple  all that has to happen is an input on the pic  is brought low the pic senses this and changes the lights accordinly. in the circuit R1 pulls the input high all the time while sw1 is not short when sw1 is short due to the magnet passing it i will pull...
  10. I

    Thermistor with op-amp

    here is how i see it but still does not explain the pot in the 'wrong' place the op amp is connected as an open-loop differential amplifier or voltage comparator, and it s action is such that its output is driven to positive saturation if its negative terminal is  more that a few hundred...
  11. I

    Special IR Circuit

    a circuit for which one would you like 1  2 or 3 ?
  12. I

    Using multiple monitors - Help?

    in my day i did a little monitor repair and i made this circuit using buffers and it ran 24 monitors i look around and see if  i can find the drawing somwhere in my attic failing that i maight be able to find the actuall device and rip it apart to see  what i used just cant remember.
  13. I

    Special IR Circuit

    since you are working with a pic there are a number of ways one could solve your problems !) inductance pick up: your emergency vehicle could have a magnet connected under it , a reed switch could be positioned under the "road surface" when the emergency vehicle passes the reed switch it will...
  14. I

    Thermistor with op-amp

    one thing i noticed about this circuit is the fact that the pot was placed on the usually fixed potential divider there for  no stable reference voltage would appear at the input. usually one would have a stable reference voltage to work with then adjust the temprature dependant voltage this...
  15. I

    5 minute timer where a mechanical motion is required

    maybe this is stupid but has no-one thought of adding a little salt to the water to make it a little more conductive. instead of using transistors for this is possibly just a small project. so try using the said battery conecting the globes up the way you need to and put the probes into the...
  16. I

    BGA desolder

    there are a number of ways to do this 1) a hot air pencil is a good way if you are experienced so as to not to blister the board. i use a weller wmd 3 this is a desolder station with a hot air pencil. 2) the best way is with infra red heat soldering staion with a heater bed. the heater bed...
  17. I

    LED FLASHER

    this might help a little if R1=R2=R and C1=C2=C the multivibrator is then symetrical and generates square waves of equal mark space ratio then the period of oscillation is given by the formula T=1.38RC  therefore the free running frequenct of such a multivibrator is given by the formula        ...
  18. I

    40 mhz oscillator

    managed to find a way to send the diagram goodie
  19. I

    40 mhz oscillator

    hi audioguru thanks for the advice you are correct in saying this is a audio device and there is no gain at 3mhz. please inform me how to download the schematic and then i will show you how my latest design looks see if you have any suggestions many thanks IAN
  20. I

    40 mhz oscillator

    two things,just to get everything straight, 1)a bd241 c is a npn device @ 3 amps 2) i am trying to build this circuit but i have realised that the max i can get the oscillator to do is 4mhz 3) working the midnight oil caused me to miscalculate my figures as i was drawing 50 watts off a 10 watt...
Top