Choke rating for choke input duty

[Tom Bavis]

Input of the choke to ground. in parallel with the choke would work as well, but it would pass high frequency noise, not desirable.

[cbutterworth]

Tom,

Excuse my ignorance, but how is the choke input to ground different than in parallel with the choke??

Are you saying that I should connect it from choke input directly to the IEC ground, or star-ground on the PCB?

This is how things are set-up right now:

transformer; diode bridge recitifer; schottky; choke; cap; choke; cap with B+ to the B+ pad on the Broskie PCB. For the GND of the PSU (ie. the other side of the final cap) it goes to the GND pad on the Broskie board. A wire from the GND pad of the Broskie board then runs through the 20 ohm resistor/cap/bridge network to chassis GND; chassis GND to IEC Earth.

The same predicament of what GND is (for me at least) applies to the voltage divider that I use to reference the AC heaters to 1/4 B+. Voltage comes into the divider from the final cap (B+ lug) and goes to ground on the final cap (the non-B+ lug). I have wondered what would happen if I took the voltage divider between this cap and PCB GND, or even to the chassis gnd.

It would be easier for me to draw this wouldn't it?

Charlie

[Renron]

Charlie,
What is the purpose of this R/C/B? network?
Why didn't you just run GND Pad to chassis earth?
Is this the "safety" ground I've read about?

Another newbie question, I am using a seperate transformer for 12.6 heater supply, with the B+ bias of 1/4 to 1/2 B+ should the caps in the HS be rated for the 12.6V (30V caps) or 12.6 + 65V (100V minimum)?
I realize the HS is ~12.6 as relative to itself, and not chassis GND (earth) but does the Cap value pertain to the overall Voltage?

One more Q if you please....
Is the B+bias to heater wire tied directly to the (-) of the heater on the PCB? or am I totally lost????

Thanks as always for your time Charlie.
I think your questions were great! I must be learning something.

Ron

Originally posted by cbutterworth
Tom,

Excuse my ignorance, but how is the choke input to ground different than in parallel with the choke??

Are you saying that I should connect it from choke input directly to the IEC ground, or star-ground on the PCB?

This is how things are set-up right now:

transformer; diode bridge recitifer; schottky; choke; cap; choke; cap with B+ to the B+ pad on the Broskie PCB. For the GND of the PSU (ie. the other side of the final cap) it goes to the GND pad on the Broskie board. A wire from the GND pad of the Broskie board then runs through the 20 ohm resistor/cap/bridge network to chassis GND; chassis GND to IEC Earth.

The same predicament of what GND is (for me at least) applies to the voltage divider that I use to reference the AC heaters to 1/4 B+. Voltage comes into the divider from the final cap (B+ lug) and goes to ground on the final cap (the non-B+ lug). I have wondered what would happen if I took the voltage divider between this cap and PCB GND, or even to the chassis gnd.

It would be easier for me to draw this wouldn't it?

Charlie

A wire from the GND pad of the Broskie board then runs through the 20 ohm resistor/cap/bridge network to chassis GND;

[Renron]

Charlie,
What is the purpose of this R/C/B? network? A wire from the GND pad of the Broskie board then runs through the 20 ohm resistor/cap/bridge network to chassis GND;
Why didn't you just run GND Pad to chassis earth?
Is this the "safety" ground I've read about?

Another newbie question, I am using a seperate transformer for 12.6 heater supply, with the 1/4B+ bias, should the caps in the HS be rated for the 12.6V (30V caps) or 12.6 + 65V (100V minimum)?
I realize the HS is ~12.6 as relative to itself, and not chassis GND (earth) but does the Cap value pertain to the overall Voltage?

I've read that a MOV across the + and GND at the Power switch will help prevent turn on/off thump? Any experience with this?

One more Q if you please....
Is the B+bias to heater wire tied directly to the (-) of the heater on the PCB? or am I totally lost????


Thanks as always for your time Charlie.
I think your questions were great! I must be learning something.

Ron

Originally posted by cbutterworth
Tom,

Excuse my ignorance, but how is the choke input to ground different than in parallel with the choke??

Are you saying that I should connect it from choke input directly to the IEC ground, or star-ground on the PCB?

This is how things are set-up right now:

transformer; diode bridge recitifer; schottky; choke; cap; choke; cap with B+ to the B+ pad on the Broskie PCB. For the GND of the PSU (ie. the other side of the final cap) it goes to the GND pad on the Broskie board. A wire from the GND pad of the Broskie board then runs through the 20 ohm resistor/cap/bridge network to chassis GND; chassis GND to IEC Earth.

The same predicament of what GND is (for me at least) applies to the voltage divider that I use to reference the AC heaters to 1/4 B+. Voltage comes into the divider from the final cap (B+ lug) and goes to ground on the final cap (the non-B+ lug). I have wondered what would happen if I took the voltage divider between this cap and PCB GND, or even to the chassis gnd.

It would be easier for me to draw this wouldn't it?

Charlie

[Renron]

Sorry for the Double tap....WOB