Filter Choke for power supply

[duke37]

Colin

There are things that I know and things that I do not know and things that I don't know I know. I only know that my transmitter kits had expensive chokes in them so they were not free.

Going back to the question I have assumed that the load is 100mA or 6KΩ and the choke is 10H.
The ripple on the first capacitor will be about 5% and the voltage attenuation of the LC filter will be over 100.
I will try to get a copier going in the next decade so I could copy the graphs from the 'Electronics Designers' Handbook'.
There is no one answer,it all depends on what is wanted.

Edit
I see that the voltage requirment has dropped from 600V to 180V.

 

[Y2KEDDIE]

I'm Bad: (or is it "My Bad").

I started talking about a 600VDc supply . Now I've shifted to 180VDC.

Originally, and still do, wish to know how to calculated the needed values.

I made up the scenario ,of a 600VDC transmitter. Realizing now you need more parameters I decided a more practical application.

I now changed to a 180VDC supply and a practical application of my LM-13 Freq. Meter /Oscillator.

I measured 6mA draw when I connected to my unregulated variable bench supply.
This equipment originally was designed for use with (4) 22-1/2 batteries (180VDC), so I don't know how much ripple it will tolerate.

The Load is a LM-13 Heterodyne Frequency meter. I measured the load, which is 6mA. Its just an oscillator, so the current draw is pretty much constant, even with modulation, the current doesn't increase more than .5 mA.

 

[hevans1944]

You will probably also want a 12 VDC power supply to replace the two series-connected "A" batteries used for filament power. Would NOT recommend using two series-connected 6.3 VAC filament secondary windings on your power transformer for this purpose, unless you don't mind a little 60 Hz "hum" modulating the RF output. Note that two of the three tubes have their 6.3 V filaments connected in series and the third tube has a current-limiting resistor in series with its filament. All the tubes have indirectly heated cathodes, so perhaps you could get away with AC filament excitation, but remember this was battery-operated portable equipment designed for shipboard Navy use during wartime conditions, so who knows what kind of "line operated" power it requires or will tolerate and still meet its original specifications (which are quite good!).

BTW, for what its worth, I agree with @Colin Mitchell on using a resistor instead of choke in a plate power supply for this rig.

 

[duke37]

Four 22.5V batteries will give 90V.

 

[Y2KEDDIE]

My Bad again!, I meant (4) 45 V batteries. Thanks Duke!

I have B C-221 as well, but that's a different project. The LM-13 (current project) uses (4) 45 V batteries.

I was planning on using a 12V, 1000 mA wall-wart for the filaments, It measures 14 VDC when connected to the filaments, I hope that's not too much.

 

[Y2KEDDIE]

If your interested, this is how I mounted the wall-wart in my chassis:

 

[hevans1944]

Four 22.5V batteries will give 90V.

The LM-13 instrument uses four 45 V batteries to provide 180 V.

 

[Y2KEDDIE]

Looking at the schematic and circuit description of the LM-13, it appears it actually runs with 135 V. The 180V of battery (4 X 45V), is then regulated by a series resistor and two Neon regulator bulbs. It has the option of 260- 475 volt operation with repositioning of a link, or 200-260V in the battery position.

I'm thinking my external supply need not be too critical or complex, in that the regulating circuitry is already in the unit. As long as I have a little more than 135V,it should work well.

 

[hevans1944]

Looking at the schematic and circuit description of the LM-13, it appears it actually runs with 135 V. The 180V of battery (4 X 45V), is then regulated by a series resistor and two Neon regulator bulbs. It has the option of 260- 475 volt operation with repositioning of a link, or 200-260V in the battery position.

I'm thinking my external supply need not be too critical or complex, in that the regulating circuitry is already in the unit. As long as I have a little more than 135V,it should work well.

Yep, I agree. Go fer it!

 

[Y2KEDDIE]

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