Capacitor halved in value? - UK Vintage Radio Repair and Restoration Discussion Forum

CambridgeWorks · 28th Jan 2021, 11:19 am

Following on from the other thread about doubling in value, somewhere I have a TCC visconol 8uF 800V that reads 4uF. I have sometimes tested others and they are always within 10% tolerance.
Could it be that the 8uF is made up by two 4uF in parallel?
Rob

GMB · 28th Jan 2021, 12:16 pm

Read how?

There are so many ways and most of them do not work well in situations where there is something not right.

CambridgeWorks · 28th Jan 2021, 1:04 pm

Tested on an oldish digital capacitance meter and a Marconi TF2700, plus tested with a 500V megger to make sure no leakage and holds charge. Several other were tested at the same time and were ok as expected.
Rob

GMB · 28th Jan 2021, 2:59 pm

That sounds like a valid measurement.
I think the rectangular kind are indeed as you say. I once saw a photo that seemed to show that.

CambridgeWorks · 28th Jan 2021, 4:55 pm

Thanks. I have seen 4uF, not sure if 600v or 800v that seem same length but more square shape. Two side by side being approx the size of my 8uF, iirc.
Rob

28th Jan 2021, 11:19 am	#1
CambridgeWorks Nonode Join Date: Jun 2010 Location: Spalding, Peterborough, Cambridgeshire, UK. Posts: 2,858	Capacitor halved in value? Following on from the other thread about doubling in value, somewhere I have a TCC visconol 8uF 800V that reads 4uF. I have sometimes tested others and they are always within 10% tolerance. Could it be that the 8uF is made up by two 4uF in parallel? Rob __________________ Apprehension creeping like a tube train up your spine - Cymbaline. Film More soundtrack - Pink Floyd

28th Jan 2021, 12:16 pm	#2
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,094	Re: Capacitor halved in value? Read how? There are so many ways and most of them do not work well in situations where there is something not right.

28th Jan 2021, 1:04 pm	#3
CambridgeWorks Nonode Join Date: Jun 2010 Location: Spalding, Peterborough, Cambridgeshire, UK. Posts: 2,858	Re: Capacitor halved in value? Tested on an oldish digital capacitance meter and a Marconi TF2700, plus tested with a 500V megger to make sure no leakage and holds charge. Several other were tested at the same time and were ok as expected. Rob __________________ Apprehension creeping like a tube train up your spine - Cymbaline. Film More soundtrack - Pink Floyd

28th Jan 2021, 2:59 pm	#4
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,094	Re: Capacitor halved in value? That sounds like a valid measurement. I think the rectangular kind are indeed as you say. I once saw a photo that seemed to show that.

28th Jan 2021, 4:55 pm	#5
CambridgeWorks Nonode Join Date: Jun 2010 Location: Spalding, Peterborough, Cambridgeshire, UK. Posts: 2,858	Re: Capacitor halved in value? Thanks. I have seen 4uF, not sure if 600v or 800v that seem same length but more square shape. Two side by side being approx the size of my 8uF, iirc. Rob __________________ Apprehension creeping like a tube train up your spine - Cymbaline. Film More soundtrack - Pink Floyd