Please identify - Oscillators?

Discussion in 'General Electronics Chat' started by Imdsm, Aug 22, 2011.

  1. Imdsm

    Thread Starter Member

    Feb 11, 2011
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    0
    Hi there,

    I bought something from ebay a while back and got a goody bag. I've just been looking through it and have pulled out what I think (and hope) are oscillators.

    I've had a look around the net trying to identify them but I've not had much luck, so I've taken a photo.

    [​IMG]

    If you could help me identify / confirm that these are oscillators, it will help me out a great deal.

    Thanks!

    (P.S, Sorry if the photo appears to be portrait, something odd seems to have happened!)
     
  2. Kingsparks

    Member

    May 17, 2011
    118
    5
    Those appear to be crystals. Used in oscillators but not in and of themselves oscillators.
     
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  3. Imdsm

    Thread Starter Member

    Feb 11, 2011
    39
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    Ah I see, most of them have two legs, but one as you can see has three and two of the others - B10.318TC and B10.3G8TC have three legs.

    In the circuits I have seen for simple radio circuits, oscillators have 3 legs (and sometimes one unused), but with two, how would I use that to oscillate a signal?

    Thanks for the help identifying them!
     
  4. Imdsm

    Thread Starter Member

    Feb 11, 2011
    39
    0
    Basically what I want to do, is have two breadboards, one a receiver and one a transmitter. On the transmitter I want to press a button and it transmit an on signal, on the recv I want to be able to detect that and light up and LED. I think this would be a good starter radio quest. Any ideas? Maybe I should make a new thread.. I think I will!

    http://forum.allaboutcircuits.com/showthread.php?p=392279#post392279
     
  5. bertus

    Administrator

    Apr 5, 2008
    15,648
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  6. Kingsparks

    Member

    May 17, 2011
    118
    5
    The three leg crystals I am familiar with use the third leg is a shield ground. I'm not saying that is always the case but in my experience it is so. As to an oscillator using one.. Well that would depend on the frequency, your use for the oscillator and your level of expertise. Let me do a search, or you can, with Google and recommend a good site for oscillator circuits. Maybe someone else on the forumn has a link but I'm not doing much right now so I'll look. There are a blue jillion of them. (Lots in other words.)
     
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  7. Imdsm

    Thread Starter Member

    Feb 11, 2011
    39
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    Thanks Bertus, I'll have a read through that, great link!

    Well basically I want to have two circuits, TX and RX. A switch on the TX circuit will send an ON signal, and the RX circuit will like up an LED when the on signal is received, with LED being off when no signal is received. From this I will learn how to send and also detect pulses, which I can then use in a microchip to make my own communication protocol - the programming part is easy peasy for me, but the electronics is where the coffee supplies get low!

    Thanks for the help btw!
     
  8. Kingsparks

    Member

    May 17, 2011
    118
    5
  9. Kingsparks

    Member

    May 17, 2011
    118
    5
    Hey Bertus.

    Your right, that had completly slipped my mind. Been a while since I worked with crystals. Thanks.
     
  10. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The items with 3 pins are most likely still crystals, but the center pin grounds the case - which is not connected to either side of the xtal.

    I'm attaching a couple of circuits.

    The first one is a generic xtal tester. The nice thing about it is that you don't need an O-scope to see if the crystal is working or not; just plug one in. If the xtal is good, the LED will light up.

    The 2nd circuit is a simple crystal oscillator made from a 4093 quad Schmitt-trigger NAND gate, a few caps and a couple resistors. The 4093 may not be fast enough for some of your crystals; you can use a couple gates from a 74HC14 hex Schmitt-trigger inverter instead; but then you'll need to use 3.3v-6v for Vcc/Vdd.

    If you want to use ICs that don't have Schmitt triggers, you will need a different configuration.

    But, square wave generators make for lousy transmitter/receiver base frequency generators, as there are far too many harmonics. A square wave consists of the fundamental frequency, plus ALL of the odd harmonics of the fundamental.
     
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  11. KJ6EAD

    Senior Member

    Apr 30, 2011
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