Please identify - Oscillators?

Thread Starter

Imdsm

Joined Feb 11, 2011
39
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.



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!)
 

Thread Starter

Imdsm

Joined Feb 11, 2011
39
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!
 

Kingsparks

Joined May 17, 2011
118
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.)
 

Thread Starter

Imdsm

Joined Feb 11, 2011
39
Hello,

The three pins items could also be some crystal filters.

The two pins items are crystals.

This page from the EDUCYPEDIA has a lot of information on crystal-osillators:
http://www.educypedia.be/electronics/analogoscicrystal.htm

Bertus
Thanks Bertus, I'll have a read through that, great link!

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.)
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!
 

SgtWookie

Joined Jul 17, 2007
22,219
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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