[Johnson] Johnson 154-2-5 variable capacitor

[Gary Schafer]

You don't even need a known inductor. Just put a fixed capacitor in 
place of the variable with a value that is close to what you think the 
variable is. Then trim it up with other fixed capacitors or a different 
one until it dips with fixed capacitors at or near where the variable dips.

73
Gary  K4FMX

Jim Brannigan wrote:
> If no one has specific information you can do this:
> Parallel a known inductance with the capacitor.
> With a grid-dip meter, measure the resonant frequency at MAX and MIN.
> capacitance.
> The Handbook has the formulas for deriving the capacitance from the known
> frequency and inductance.
> 
> Measure the distance between any two plates (rotor and stator) refer to the
> Handbook for the max breakdown voltage for an air insulated capacitor.
> 
> Jim
> 
> 
> 
>>I have a Johnson 154-2-5 variable capacitor. Looked on the Cardwell web
>>site and the closest I could come was a 154-2-1.
>>
>>Anyone have specifics on the 154-2-5? Peak withstanding voltage, max and
>>min capacitance, air gap?
>>
>>Thanks.
>>
>>Steve K8JQ
> 
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