1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

Simple gated oscillator

Discussion in 'Electronic Projects' started by sheldonstv, Jun 8, 2009.

Thread Status:
Not open for further replies.
  1. sheldonstv

    sheldonstv New Member

    Joined:
    Jul 15, 2005
    Messages:
    230
    Likes:
    6
    Location:
    Newcastle upon Tyne, United Kingdom
    Heres a simple gated oscillator for you to play with,its nothing complicated build wise but does give an insight as to how rs latches can be used(for switch debounce) and gating a simple osc. on or off....you can play around with the component values if you wish and the output transistor you could flash an led or control a relay etc or feed the signal to the clk ip on a counter(4017 etc)
    regards mike
     

    Attached Files:

    Last edited by a moderator: Jul 16, 2009
  2. JBrock

    JBrock Member

    Joined:
    Feb 8, 2009
    Messages:
    48
    Likes:
    1
    Location:
    Carlsbad CA
    I give it a B+ !

    I like it. I am very curious; what software did you use to create the schematic?

    Here are my impressions:
    > You should label the switch positions. All those NANDS get confusing. It looks like it is shown in the "OFF" position.
    > I assume you have tested it, but you did not state that.
    > Why would you use a transistor and pull-up for a clock? The output of the CMOS device U1D is active high and low with better characteristics.
    > Where in the world do you get a 33k pot!?
    > That oscillator has some weak properties. You could build a better one using two gates.
    > What's up with all the connection dots? They are only needed where wires meet, not on component pins.
    > Add a bubble to indicate the +12V connection.

    Thanks for the contribution.
     
  3. BrownOut

    BrownOut Banned

    Joined:
    Jun 10, 2009
    Messages:
    4,630
    Likes:
    60
    Location:
    Huntsville, Alabama USA
    Like what?
     
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. JBrock

    JBrock Member

    Joined:
    Feb 8, 2009
    Messages:
    48
    Likes:
    1
    Location:
    Carlsbad CA

    It's a MM Grade Oscillator

    The cap charges only through the range of the hysteresis band on the input of the gate. This results in poor frequency stability and little repeatability across different manufacturers. The frequency cannot be calculated with any accuracy. Almost any desirable characteristic is lacking, other than low component count. This oscillator is definitely in the Mickey-Mouse league of electrical design.
     
  6. sheldonstv

    sheldonstv New Member

    Joined:
    Jul 15, 2005
    Messages:
    230
    Likes:
    6
    Location:
    Newcastle upon Tyne, United Kingdom
    the circuit software was circuitmaker 6 which does that connection wise on components where my copy of designworks is different and doesnt do that so much, the 33k preset was one of many wyhich i have lying around ...and i have used that type of osc for many different things and yes the circuit does work its been built and tested....the spdt switch is actually in the off position-in that position the osc is disabled -I had an instance once where a 555 had a very short life when directly connected to a 4017 clk ip (for some reason)and adding an extra transistor cured it,this particular schematic isnt designed to be super fantastic but it does work and quite a few items out there use that sort of osc.....dont be scared of the 4093.....:D
     
    Last edited: Jun 16, 2009
  7. Hero999

    Hero999 Banned

    Joined:
    Apr 6, 2006
    Messages:
    14,902
    Likes:
    79
    Location:
    England
    It depends on what you're using it for.

    If all you want to do is flash an LED then I don't see any harm in using it.
     
  8. BrownOut

    BrownOut Banned

    Joined:
    Jun 10, 2009
    Messages:
    4,630
    Likes:
    60
    Location:
    Huntsville, Alabama USA
    I still don't know how using two gates solves the shortcommings.
     
  9. sheldonstv

    sheldonstv New Member

    Joined:
    Jul 15, 2005
    Messages:
    230
    Likes:
    6
    Location:
    Newcastle upon Tyne, United Kingdom
    the second gate on the output side of the osc ensures the output transister would be off as when the osc is disabled the output goes hi.....
     
Thread Status:
Not open for further replies.

Share This Page