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  1. MP1

    Telephone Billing machine!!!

    Here is an interesting thought... you could put these numbers on a card and call it a calling card.... Hmmmm...has some familiarity to it....  ;D You sure this hasn't already been invented? MP
  2. MP1

    LED sequencer-need help

    I think you should draw a picture. MP
  3. MP1

    Can you put a dimmer on LEDs?

    It would be a fairly uncommon circuit to generate heat at this point with a standard LED. Any circuit which normally uses a resistor as a current limit to the LED can use a pot to adjust the brightness. Don't forget to use a resistor in series with the pot, because the pot will allow zero...
  4. MP1

    Laser&Electro-Optics

    I work with lasers, as well. However, unlike Kevin, I have never tickled one.  ;D ;D Fatal_byte:  You should ask specific questions, this is a very big area of electronics. I am sure there are many members on this forum who have experience in this area. MP
  5. MP1

    LED sequencer-need help

    A 4017 doesn't care if you turn one of the LEDs off. It will keep on sequencing. If you need to fill in the gap for a missed sequence, you can make this a little smarter with digital gates. MP
  6. MP1

    pc controlled electrical applicances

    Manoj, What do you want to know? If you can write a program to turn a bit on or off on the parallel port, you can use that bit to trigger a SSR. The SSR can turn the appliance on or off. I think you did not get much response because your question was very general. MP
  7. MP1

    Delayed power on / flip circuit help

    In monostable, the 555 triggers on a negative-going input signal when the level reaches 1/3 VCC. Once triggered, the circuit remains in this state until the set time has elapsed, even if it is triggered again during this interval. The duration of the output HIGH state is given by t = 1.1 R1C1...
  8. MP1

    Delayed power on / flip circuit help

    Why not use a 555 monostable for your delay? Just invert it and toggle. MP
  9. MP1

    Power Amp

    ...as requested, here is a power amp with no ICs. (click on file name to see larger version) MP
  10. MP1

    Digital Voltmeter with a twist

    toss the reed switches and use a LM3914 MP
  11. MP1

    Impedance matching.

    Your output must be 8 ohms for the speaker load, thus you will need to use the same or very close. MP
  12. MP1

    laser lights

    It will be better to use a voltage regulator instead of a pot. Especially when you are powering more than one device at different voltages. The resistance of the pot will become part of ohms law of your other branch of the circuit. Load will shift. In other words, you will never get a steady...
  13. MP1

    got any idea?

    jai, A microprocessor is what is in a computer (Central Processing Unit or CPU). I think you mean a microcontroller. A microcontroller runs a small program. You will find many peripherals attached to a computer with microcontrollers communicating back and forth with the microprocessor. They free...
  14. MP1

    help needed hooking up 4 lm3914

    The amount of resistance between pin 7 and pin 8 (which is grounded) determines the LED brightness on a LM3914. This is because you have a constant 1.25 volts reference between pins 7 and 8. MP
  15. MP1

    photo PCB

    It is a combination of light intensity from the bulb and distance from the PC board. You will want to kill a board for learning purposes. Tape the transparency to the board. Put strips of black cardboard or some other material that is light tight (side by side) on the transparency and remove a...
  16. MP1

    Most interesting electronics-area?

    Cody, You know you are running with the big dogs when you like 2048.... MP
  17. MP1

    MP3 PLAYER

    Siddharth, You need to click on the "Hardware" link on the left. Here is one of the pages: http://www.myplace.nu/mp3/yampp3.htm USB model: http://www.myplace.nu/mp3/yampp3u.htm Clicking on the schematics will open them in a new window. Click on the software links on the left to get the cource...
  18. MP1

    RBG LED how to?

    madthug, Here is a link where you might be able to get samples: http://www.lc-led.com/Products/department/27?OVRAW=rgb%20led&OVKEY=rgb%20led&OVMTC=standard You will need to form a matrix for the color switching with the micro or use a lot of pins. MP
  19. MP1

    TSL220

    Here is the block diagram from TI. MP
  20. MP1

    Charging a 9V rechargable battery using two 9V dc Motors

    FlipFlop, You will need more than 9 volts to charge a 9 volt battery to capacity. You will also want to regulate the charge so that you do not over charge the battey with your charge generator. This can be done by changing the speed of the rotor or by a regulation circuit. Are you sure the...
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