[ARC5] Crystal Testers

[Glenn Little WB4UIV]

Many years ago, I built a crystal oscillator that ran on a 9V battery.
I think that it was in an ARRL handbook.
Being younger, cheap and innovative, I built this as a versatile 
handheld piece of test equipment.
I modified the original design by using a polarity reversing switch on 
the battery.
I placed a current meter in the collector lead of the oscillator 
transistor (the only transistor in the instrument).
I added a transistor socket and a number of crystal different sockets in 
parallel.
With the switch in the PNP position and a known good PNP transistor I 
could place an unknown crystal in the socket and press the test button 
(in series with one lead of the battery).
The meter would read collector current proportional to the crystal activity.
I could do the same for an NPN transistor.
Now I have a known good crystal.
I can now test unknown transistors and see how well the oscillate at the 
crystal frequency.
I did not have a frequency counter then, but, now have added a BNC 
connector capacitively coupled to the transistor collector.
I can use this to measure the crystal frequency.

With this inexpensive piece of equipment, I can determine if a 
transistor is PNP or NPN, I can see crystal activity, I can measure 
crystal frequency and select a transistor for best gain a a specific 
frequency.

It will not measure crystal load parameters, by will give an indication 
of crystal activity.

73
Glenn
WB4UIV


On 6/12/2016 11:36 AM, n2lxm at juno.com wrote:
> I have built many testers over the years. Her is a list of what I have on
> the test bench now.
>
> Simple Pulsed Crystal Signal Source,  March 1992 73 Magazine
>
> Improved Crystal Tester,  Jan 1992 73 Magazine
>
> The Crystal Tester, by W6BLZ ( the one I sent some members )  July 1964
> CQ Magazine
>
> Crystal Controlled Signal Source ARRL Hand Book.
>
> Each has it's strong points. I have found that the semiconductor types,
> sometimes do not have enough current to drive sluggish crystals into
> oscillation. So my go to unit is the one by W6BLZ.
>
>
>                                                     Jeff N2LXM
>                                                       American
>                                                         Patriot
>                                     Proud Father of Two U.S. Marines
>
> ____________________________________________________________
> Blazeray
> Deemed: One Household Item Everyone Should Have In Any Emergency
> http://thirdpartyoffers.juno.com/TGL3141/575d81cc8db801cc0d57st04vuc
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

-- 
-----------------------------------------------------------------------
Glenn Little                ARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIV            wb4uiv at arrl.net    AMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
---------------------------------------------------------------------------