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Tube rectifiers often specify the minimum resistance required in series with each rectifier to limit peak current. For full-wave rectification, does the source resistance shown in PSUD refer to the whole secondary winding or, as with the voltage, half of it?

PSUD shows the source impedance (combination of primary and secondary impedance) for just one leg of the winding.

You can directly add the series resistance to this value to simulate the current limiting resistors specified by the manufacturers.

Regards,
Duncan

Thanks very much for the reply.

Just to be clear, if I need 100R in each leg, I just enter the secondary winding resistance as100R and this value will be applied to each leg when calculating?

There's a little bit more to it. The transformer impedance is, for the most part, caused by the primary winding resistance and the secondary winding resistance - both will affect the impedance feeding the remainder of the PSU.

In addition to this, you may want to add some limiting resistors. The best way I can think to illustrate this, is if you pull up the choke_input.psu file from the examples folder (on my machine it's?C:\Program Files (x86)\PSU Designer II\examples). This shows a source impedance per leg of 130 ohms.

If you want to have a 100 ohm limit resistor, simply change the source impedance to 230 ohms (130 + 100) and so on.

Should you need more info on how to figure out the 130 ohms impedance of the basic transformer in the first place, please shout and I can walk through some examples.

Regards,
Duncan

Thanks, I think I get it now, although I believe it is usual to include the winding resistance in the total limiting resistance, rather than adding it, when using capacitor input.

Your plan to include a hybrid bridge option in PSUD3 will make this a lot simpler!

Best regards,

Richard.