[Boatanchors] selenium rectifier replacement

Dick KF4NS kf4nsradio at verizon.net
Tue Jan 30 12:43:38 EST 2007


I am making my first substitution for a selenium rectifier and have seen all 
the info on the list about this process. I had not given any thought though 
to the actual paramaters until now. I just realized that the series resistor 
has to be quite hefty. For my Heathkit RF signal generator, the voltage is 
125V in the secondary and the current as marked on the schematic is 100ma. 
That means I need a 12.5W resistor at about 50 ohms to start. Wow! The only 
50 ohm non-inductive resistors I have are 1/4 to 2 watts. Would the 
wirewound be a problem in this application (or maybe not since it is ahead 
of the filter capacitor)?

Next, just out of curiosity, is there a way to test the selenium? I tried 
with just an ohmmeter and also using the diode scale on my DMM. It reads out 
of limits on the diode scale and on the ohmmeter it reads 100K. Seems a bit 
high.
73, Dick KF4NS
St Petersburg, FL 33714 USA
Keep The Glow! 



More information about the Boatanchors mailing list