[Boatanchors] Capacitor info

[Glen Zook]

The filter capacitor, in the Globe Scout, actually has 2-individual capacitors in series within the cardboard tube.  I would go with 2-each 450-volt 33 mfd capacitors and put them in series.



Modern capacitors have a much closer tolerance than the old capacitors.  Many of the older capacitors had a tolerance of like -50% / +80%.  That meant the effective capacitance of the original capacitor could be a low as 6 mfd or as high as over 21 mfd.  Modern capacitors are available in either +/- 10% or +/- 20%.  Using 33 mfd capacitors at 20% would give a range of a little over 13 mfd to almost 20 mfd which fall well within the range of the old capacitor.



I would put a 100K resistor across each of the 33 mfd capacitors to equalize them.  2-watt would be a minimum and 5-watt would definitely be enough.



I get virtually all my parts from Mouser:



http://www.mouser.com



They have no minimum order for the United States.

 Glen, K9STH 
Website: http://k9sth.net
 

      From: Glenn Little WB4UIV <glennmaillist at bellsouth.net>
 To: boatanchors at mailman.qth.net 
 Sent: Sunday, January 31, 2016 7:51 PM
 Subject: [Boatanchors] Capacitor info
   
Where can one find a 12 uF 650 VDC capacitor?
A friend of mine asked me and I do not know.
He bought a transmitter, I think it was a Globe Scout, and he needs a 
new filter capacitor.

Any help with a source appreciated