[Milsurplus] Identify Modulation Transformer

[antqradio at juno.com]

John
If you have access to an audio oscillator, it is a simple task to find
the unknown winding impedance.  Terminate the secondary with 6.5k and
connect the audio oscillator to both the primary winding in series with a
pot or decade resistance box.  Measure the voltage drop across the
transformer primary and the pot with two similar high impedance DVMs or a
two channel o'scope.  When voltages are equal, the pot has the same
resistance as the transformer's impedance.  Frequency doesn't seem to
matter much as long as you are in the normal audio ranges.

I just did this last week looking for a suitable single ended audio
output transformer for a BCB-SW table radio.  I checked it at 1000 cps
and 400 cps, both measurements agreed.  Speaker had been removed by a
budding ham about 30 or so years ago.  His sister wants to surprise him. 
Well, that is what she told me.!

My ideas for checking transformer power rating may be too controversial
for the list!

Regards,
Jim

On Wed, 15 Dec 2004 06:21:03 -0800 (PST) John King <k5pgw at yahoo.com>
writes:
> I have a military modulation transformer with some of
> the impedances obliterated.
> 
> The readable markings are as follow:
> 
>         PART AM- 7195 TEST 10000 V.
>         FAMILY 14 GRADE 1 CLASS A
> 
> The impedance of the secondary is 6500 ohms.
> The impedance of the primary has been obilterated and
> that is the value i need to determine.
> 
> The transformer was manufactured by MERIT and measures
> 10.5 inches high (to top of insukators) by width of
> 5.75 inches by depth of 6 inches. It weighs 34 lbs. It
> is/was Gray in color.
> 
> Can anyone identify this transformer for me and
> provide specs on it? Thanks and 73, John, K5PGW
> 
> 
>                 
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