Re: cheap way to test "doorknob" capacitors? (fwd)

[<sroys@xxxxxxxxxxxxxxxxx>]

---------- Forwarded message ----------
Date: Wed, 10 Nov 2004 19:31:13 -0600
From: Shaun Epp <scepp@xxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: cheap way to test "doorknob" capacitors? (fwd)

I read that the capacitance of door knob caps are a function of voltage. 
The capacitance is higher at high voltages.

shaun


----- Original Message ----- 
From: "High Voltage list" <hvlist@xxxxxxxxxx>
To: "hvlist" <hvlist@xxxxxxxxxxxxxxxxx>
Sent: Wednesday, November 10, 2004 4:26 PM
Subject: Re: cheap way to test "doorknob" capacitors? (fwd)


> Original poster: <sroys@xxxxxxxxxxxxxxxxx>
>
>
>
> ---------- Forwarded message ----------
> Date: Thu, 11 Nov 2004 09:06:49 +1300
> From: Malcolm Watts <m.j.watts@xxxxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: Re: cheap way to test "doorknob" capacitors? (fwd)
>
> On 8 Nov 2004, at 15:05, High Voltage list wrote:
>
>> Original poster: <sroys@xxxxxxxxxxxxxxxxx>
>>
>>
>>
>> ---------- Forwarded message ----------
>> Date: Mon, 8 Nov 2004 00:08:42 -0500
>> From: Jack Vandam <snotoir7674g@xxxxxxxxxxxxxx>
>> To: High Voltage list <hvlist@xxxxxxxxxx>
>> Subject: cheap way to test "doorknob" capacitors?
>>
>> I have just come across an assortment of used doorknob capacitors.
>> Since I don't know whether or not they work, I would like to test
>> them.  What would be a simple way of doing this?
>
> To check their capacitances you could marry them individually with a
> known inductance and check the resonant frequency of the resulting
> tank. In my experience, used doorknobs may well be down on
> capacitance if they've been thrashed as the metallization can't
> handle large currents.
>
> Malcolm
>
>
>