this is my first post so I apologize if I do not follow any sort of convention.

I have researched how Center-Tapped Full Wave Rectifiers should work and from what I found, when the turns ratio is 1:2, then the voltage across each of the two inductors on the secondary side should be equal to the voltage input (Vin = VLS1 = VLS2).

I tried to model the circuit in LTspice, however my results were inaccurate as the voltages VLS1 and VLS2 are twice the input voltage. Could someone please point out where the circuit model went wrong?

Shown here is my attempt to model a CT Full wave rectifier in LTspice

Thank you very much.

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    \$\begingroup\$ But 1:2 is a step-up transformer, you want 1:1 thus Ls = Lp web.cecs.pdx.edu/~tymerski/ece222/… \$\endgroup\$
    – G36
    Jun 11, 2021 at 19:49
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    \$\begingroup\$ 1:4 L ratio ought to tell you N^2 =4 Z and V ratio is 1:2 \$\endgroup\$ Jun 11, 2021 at 19:57
  • \$\begingroup\$ Thank you for the comments, my mistake was that I assumed LS1 = LS2 = L2 = LP/(N1/N2)^2. \$\endgroup\$ Jun 11, 2021 at 20:11

1 Answer 1


I think it is not the case. There are 3 inductors coupled (one primary , and two secondary), thus the values of all inductors must be 1 H. Regarding the 2 secondary as one ... you must have 1H (ex : 1000 turns) for primary, and 4H for secondaries (which are coupled). Because of the turns number (2000 turns), and coupling is perfect. So LS1 and LS2 must be equal to LP. Change the values in Switchcad or LTspice XVII, I presume.

In fact, the transfo is a 1/1:1

  • \$\begingroup\$ Thanks for the answer. \$\endgroup\$ Jun 11, 2021 at 20:11

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