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Generating 50hz Freq Question.

Discussion in 'Electronic Basics' started by Wilhelm Lehmann, Jun 14, 2004.

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  1. Hi,

    I am relatively new to electronics, but understand the basics at least.
    Using a 555 and R + C, I can create a 50hz oscillation, but it seems not to
    be very accurate.

    I understand using crystals is much more acurate, but need to find how to
    manage the oscelation at 50hz. Using a PIC16F74 works but defeats my goal of
    making it simple. ( ie no programming) Is there a circuit that I can use,
    maybe with a cmos counter using a 4mhz (or other value) crystal to generate
    the 50hz ? (switching 2 transistors on and off alternativly)

    Thanks in advance.

  2. John Fields

    John Fields Guest

    You can get an Epson C-2 25.60000K-P (25.6kHz) crystal and a 74HC4060
    ripple counter/oscillator from Digi-Key, and Q9 of the counter will
    give you a 50Hz output once you get it to oscillate.

    check page 12 of:

    for a schematic of a typical CMOS crystal oscillator.
  3. Thank You very much. Just what I needed.
  4. CFoley1064

    CFoley1064 Guest

    Subject: Generating 50hz Freq Question.
    Of course, the customary solution for this is to run off the 50 Hz line
    frequency. Otherwise, the customary answer is to generate an interrupt off of
    your microcontroller timer/counter using the crystal-based uC clock frequency.
    But somehow, I don't think that's what you're looking for.

    Given that, I don't think there's a one-chip solution that will get you where
    you want to go. A crystal frequency of 2.048 MHz will get you a two-chip
    solution (view in fixed font or M$ Notepad):

    50 Hz From Crystal or Oscillator
    | | .--------------.
    ..-----o-----. | | | |
    | | | CLK /2^12| | |
    | 2.048MHz o----o CD4040 o------oCLK |
    | | | | | CD4017 |
    | | | | | |
    '-----o-----' | | .-oEN |
    | | | | |
    | | | | OUT/10 |
    | | | '-------o------'
    '-----------------' | |
    === |
    GND |
    50 Hz

    A cursory scan doesn't show any crystals at this frequency from the usual
    hobbyist suspects, but you can get an SMD TTL/CMOS-compatible clock oscillator
    at this frequency from Mouser for $2.31 USD (P/N 549-C3290-2.048).

    If you could give a little more information about what you need to do, we could
    offer more advice on what to do with the 50 Hz signal to drive your output.

    Have fun.

    Good luck
  5. John Fields

    John Fields Guest

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