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  1. Hero999

    forum topic missing

    What topic? there are hundreds of topics here. I know the site went down a few days ago, it must have been lost then.
  2. Hero999

    power led drivers circuits?

    I know, I wasn't suggesting you should should use a wall wart on its own, that would be a silly idea. The idea was to use a wall wart in conjunction with the Buck puck driver I suggested previously. The driver you've suggested looks perfect for powering an LED off the mains, no need for a wall...
  3. Hero999

    power led drivers circuits?

    mir_as82, As I'm sure you've been told before, use a wall brick power supply.
  4. Hero999

    Blinking Halloween Eyes?

    I think I can see where you went wrong: it's the 74HC14. They don't, it's a totally different circuit which has nothing to do with the 555. You can use either the 555 or the 74HC14s. As you need 12, using two 74HC14s will work out cheaper than six 556s but it's up to you, it depends on what...
  5. Hero999

    Blinking Halloween Eyes?

    As I've said above, it's on the datasheet, as you appear to have forgotten how to use Google, here it is. http://tamarisco.datsi.fi.upm.es/ASIGNATURAS/FMI/COMPONENTES/MM74HC14_(InvSchmitt).pdf You only need to change the value of R2, for 4.5V and two LEDs in series use 150R. Heck way not use a...
  6. Hero999

    Blinking Halloween Eyes?

    By the way the R2 in the previous schematic should have been 47R, with 330R it 3V it would be too dim. I thought you wanted a fader? A blinker is much simpler. The pinout for the 74HC14 is on the datasheet which can be found using Google. If you want two LEDs then use a >6V power supply...
  7. Hero999

    power led drivers circuits?

    350mA is quite a lot of current for an LED. Here's a driver that will do what you want. http://www.leddynamics.com/LuxDrive/datasheets/3021-BuckPuck.pdf
  8. Hero999

    Blinking Halloween Eyes?

    Was that my circuit you built? The frequency should have been about 0.5Hz if assembled correctly. Are you sure you've not used a 220nF capacitor or soldered it in the wrong way round? The frequency is roughly equal to the following formula: F = 1.1/(C1
  9. Hero999

    MOSFET VGS

    You're not listening - there's a huge difference between a MOSFET and a BJT.
  10. Hero999

    Blinking Halloween Eyes?

    Here's the simplist way of doing it.
  11. Hero999

    Light dimmer two-wires challenge

    I replied before but it got lost,so here it is again. You can boostrap the power supply of the micro controller. Note that the duty cycle can never reach 100% because some off time is required to charge C1. You don't need a PIC, a 7555 will do. The schematic has calculations for working out...
  12. Hero999

    [b]Questions regarding Switched-Mode Power Supply[/b]

    Yes, lots of commercial power supplies are now switched mode, although one does occasionally bump into the odd linear power supply; most commonly in audio PSUs and AC adaptors.
  13. Hero999

    What the value of Zout???

    An alternative to building a transformer is to simply put a tap in the middle of the inductor, the apparent impedance of the load will be increased by a factor of four and the voltage across it will be halved so the power will be down by a factor of four.
  14. Hero999

    MOSFET VGS

    MOSFETs can be cheaply purchased with on resistances as low as 5mΩ so the voltage drop is only 50mV at 10A. I wouldn't say that 5V is a high voltage unless you want to power the device from two AA cells. Using a MOSFET invariably saves power, especially in DC applications. To achieve a good...
  15. Hero999

    MOSFET VGS

    MOSFETs have a faster switching speed, lower on loss and are easier to drive than BJTs, the gate also requires no current, at DC.
  16. Hero999

    Building a TV remote with an IR finder

    TV remote only emit IR when they're activated. A solution to the problem already exists: fit the remote with a passive transponder (similar to those used as an anti shoplifting device) which can be found using a suitable detector.
  17. Hero999

    What the value of Zout???

    Yes, the output impedance will be equal to the impedance of the inductor and capacitor in parallel. The impedance of an ideal inductor and capacitor in parallel is infinite, in reality is won't be infinite but it'll be very high and depend on the Q of the tank. Any load connected to the output...
  18. Hero999

    Fm transmitter about

    What did you use to power the transmitter? Was it a cheap unregulated wall wart or a battery or regulated wall wart/mains supply? I've tried powering an FM transmitter from a chap wall wart and it made the radio hum rather than transmit sound from the mic. You need to power it from a steady DC...
  19. Hero999

    Milliamp Question

    The amount of current that actually flows depends on the resistance and the voltage of the supply. I = V/R Where I is the current, V is the voltage and R is the resistance. The power supply will have a current rating which just specifies the maximum amount of current it can safely supply. If...
  20. Hero999

    Where the Archive ????

    This sort of question gets asked pretty often, there should be a sticky somewhere. http://www.electronics-lab.com/forum/index.php?topic=18917.msg87206#msg87206
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