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Re: Broadcast Capacitors



Subject: 
        Re: Broadcast Capacitors
  Date: 
        Sat, 29 Mar 1997 18:02:13 -0500
  From: 
        "Robert W. Stephens" <rwstephens-at-headwaters-dot-com>
    To: 
        Tesla List <tesla-at-pupman-dot-com>


> Date:          Wed, 26 Mar 1997 00:09:45 -0600
> To:            tesla-at-poodle.pupman-dot-com
> Subject:       Broadcast Capacitors
> From:          Tesla List <tesla-at-pupman-dot-com>

> Subject: 
>             Broadcast Capacitors
>        Date: 
>             Wed, 26 Mar 1997 08:03:27 +1200
>        From: 
>             "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
> Organization: 
>             Wellington Polytechnic, NZ
>          To: 
>             tesla-at-pupman-dot-com
> 
> 
> Hello all,
>              I have come by a bunch of capacitors surplus to some 
> broadcasting outfit (TV I think). The manufacturer is "Sangamo". The 
> values range from 0.001uF to around 0.0056uF. Peak voltages on the 
> units range from 4 kV for the larger capacitance to 6kV for the 
> smallest. The casing is brown and cylindrical, dimensions 50mm 
> diameter x 50mm high (2" x 2"). Quoted currents on the cases are in 
> Amps RMS at 1000kc (1MHz). Does anyone have info on these? I am 
> interested in the dielectric and possible suitability for discharge 
> applications. They look like ideal tuning caps for tube/transistor 
> coil.
> 
> Malcolm

Malcolm,

These sound like mica capacitors and will work extremely well in the 
tank circuit of a vac tube T.C. as well as RF bypass for the plate 
transformer.  They can also be used for the system cap in disruptive 
discharge T.C.'s if you series parallel a whole whack of them.  I did 
this.  I took 30 units of 0.002 mfd -at-12,500 volt peak  broadcast 
micas and arranged them in three groups of ten paralleled in series.  
The net result is about 0.007 mfd at 37,500 peak and is employed in 
my highly successful STC system using a single 15 k -at- 60 Ma neon.
I've achieved straight line discharges to 52 inches with this coil. 

If these are cheap enough, BUY THEM!!!!

Cheers,
rwstephens