UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - VTVM

6SN7WGTB · 19th Jul 2021, 5:18 pm

Am restoring a VTVM and the AC range input cap has a rating marked 1000 WVDC. It appears original - plus age and make appear to match all others in the unit.

The VTVM has a maximum input range of 1500 V AC or DC. The 1500 AC is specified as RMS, or 4200 p-p, as you'd expect.

As I understand it, DC rating of a capacitor exceeds the AC rating by definition of the RMS factor of root 2.

Sorry if I'm being a bit dim here, but what makes a 1kV DC cap suited to this 1500V AC application?

The VTVM has a tube rectifier on the AC range.

Thank you for your help.

19th Jul 2021, 5:18 pm	#1
6SN7WGTB Hexode Join Date: Apr 2021 Location: Crawley, West Sussex, UK. Posts: 442	VTVM - AC range capacitor voltage rating? Am restoring a VTVM and the AC range input cap has a rating marked 1000 WVDC. It appears original - plus age and make appear to match all others in the unit. The VTVM has a maximum input range of 1500 V AC or DC. The 1500 AC is specified as RMS, or 4200 p-p, as you'd expect. As I understand it, DC rating of a capacitor exceeds the AC rating by definition of the RMS factor of root 2. Sorry if I'm being a bit dim here, but what makes a 1kV DC cap suited to this 1500V AC application? The VTVM has a tube rectifier on the AC range. Thank you for your help.