[JMS] Millen 90800/90831 power supply and 90881 amp

[james_millen_society@mailman.qth.net]

Hi Jim:

No full wave BRIDGE rectification here. Just a diode on either side of the windings with the c.t. going to ground. I was considering a pi-network filter but it shouldn't be a big deal shifting one of the two 22 uF/450 VDC caps to the output of the supply. It will be choke input. The power supply will be supplying both the modulator and the transmitter.  Output will be "QRP", that is, the transmitter will supply around 17.5 watts input to the 90881. Hope the power supply does the trick if I restrict the power level of the modulator and the transmitter to these levels. Cal, N6KYR. 




Cal,

If you use a bridge rectifier on your power transformer you will get twice the 
voltage output but the rated continuous current will drop to half of the 250 ma 
value, so be a little careful about how warm the transformer gets.  You can pull 
only so many watts out of the transformer.  I would also suggest you consider 
making your filter a choke-input design with the capacitors on the output side.  
That will limit your high voltage output to about 0.9 times the transformer RMS 
voltage less the drop across the choke provided the choke inductance is above 
the "critical" value, L(henries) = Load Resistance (ohms)/1000.  A 
choke-input filter will also improve the regulation of the power supply.

Jim Hanlon, W8KGI



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