# [Amps] peak voltage rating for load cap

Alek Petkovic vk6apk at bigpond.com
Sat Aug 19 19:17:41 EDT 2017

```Ha! You're right.

Sorry 'bout that.

73, Alek.
VK6APK

On 19/08/2017 10:52 PM, Vic Rosenthal wrote:
> All of you guys are forgetting that he said "PI-L", not PI!
>
> Vic 4X6GP
>
>
>> On 19 Aug 2017, at 16:29, Peter Voelpel<dj7ww at t-online.de>  wrote:
>>
>> Let´s say the SWR is 3 then the load might be 150 ohms.
>> The peak voltage across the load capacitor will be 775V at 2KW.
>> That is sqrt3 higher then at SWR1.
>>
>> 73
>> Peter
>>
>>
>> -----Original Message-----
>> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Joe Subich,
>> W4TV
>>
>> That will give you average (RMS) voltage with SWR = 1:1.  For peak
>> voltage, multiply by 1.414 (peak voltage of a sine wave):  316 * 1.414
>> = 447 V.
>>
>>
>>> your system is all tuned and matched.
>>>
>> Multiply the peak voltage by the SWR for worst case peak voltage if
>> the voltage node occurs on the capacitor - 316 * 1.414 * 3 = 1340V.
>> A 1200 volt rated capacitor will be marginal in a *system* allowing
>> for a maximum SWR of 3:1 at 2 KW - it will be barely adequate when
>> the system is designed for 1500 W (1166 V).
>>
>>
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